166003220 has 54 divisors (see below), whose sum is σ = 362308842. Its totient is φ = 63889056.

The previous prime is 166003217. The next prime is 166003223. The reversal of 166003220 is 22300661.

It is an interprime number because it is at equal distance from previous prime (166003217) and next prime (166003223).

It can be written as a sum of positive squares in only one way, i.e., 132802576 + 33200644 = 11524^2 + 5762^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 166003192 and 166003201.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166003223) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2477627 + ... + 2477693.

It is an arithmetic number, because the mean of its divisors is an integer number (6709423).

Almost surely, 2^166003220 is an apocalyptic number.

166003220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 166003220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (181154421).

166003220 is an abundant number, since it is smaller than the sum of its proper divisors (196305622).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

166003220 is an equidigital number, since it uses as much as digits as its factorization.

166003220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229 (or 117 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 166003220 is about 12884.2236863538. The cubic root of 166003220 is about 549.5900195376.

Multiplying 166003220 by its sum of digits (20), we get a square (3320064400 = 57620²).

166003220 divided by its sum of digits (20) gives a square (8300161 = 2881²).

Adding to 166003220 its reverse (22300661), we get a palindrome (188303881).

The spelling of 166003220 in words is "one hundred sixty-six million, three thousand, two hundred twenty".