166205520 has 200 divisors, whose sum is σ = 621975816. Its totient is φ = 40891392.

The previous prime is 166205519. The next prime is 166205569. The reversal of 166205520 is 25502661.

166205520 is a `hidden beast` number, since 16 + 620 + 5 + 5 + 20 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 104976 + 166100544 = 324^2 + 12888^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 83254 + ... + 85226.

Almost surely, 2^166205520 is an apocalyptic number.

166205520 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 166205520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (310987908).

166205520 is an abundant number, since it is smaller than the sum of its proper divisors (455770296).

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

166205520 is a wasteful number, since it uses less digits than its factorization.

166205520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2011 (or 1996 counting only the distinct ones).

The product of its (nonzero) digits is 3600, while the sum is 27.

The square root of 166205520 is about 12892.0719824239. The cubic root of 166205520 is about 549.8131817298.

The spelling of 166205520 in words is "one hundred sixty-six million, two hundred five thousand, five hundred twenty".