166821136 has 40 divisors (see below), whose sum is σ = 343263744. Its totient is φ = 78266880.

The previous prime is 166821131. The next prime is 166821167. The reversal of 166821136 is 631128661.

It is a happy number.

166821136 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is not an unprimeable number, because it can be changed into a prime (166821131) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116521 + ... + 117943.

Almost surely, 2^166821136 is an apocalyptic number.

166821136 is a gapful number since it is divisible by the number (16) 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 166821136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171631872).

166821136 is an abundant number, since it is smaller than the sum of its proper divisors (176442608).

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

166821136 is a wasteful number, since it uses less digits than its factorization.

166821136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1879 (or 1873 counting only the distinct ones).

The product of its digits is 10368, while the sum is 34.

The square root of 166821136 is about 12915.9256733693. The cubic root of 166821136 is about 550.4911711521.

Adding to 166821136 its reverse (631128661), we get a palindrome (797949797).

The spelling of 166821136 in words is "one hundred sixty-six million, eight hundred twenty-one thousand, one hundred thirty-six".