165638529531 has 32 divisors (see below), whose sum is σ = 256180561920. Its totient is φ = 105574658112.

The previous prime is 165638529527. The next prime is 165638529547. The reversal of 165638529531 is 135925836561.

165638529531 is a `hidden beast` number, since 1 + 6 + 5 + 6 + 3 + 85 + 29 + 531 = 666.

It is not a de Polignac number, because 165638529531 - 2² = 165638529527 is a prime.

It is a super-2 number, since 2×165638529531² (a number of 23 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (54) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (165638529031) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1275070 + ... + 1398956.

It is an arithmetic number, because the mean of its divisors is an integer number (8005642560).

Almost surely, 2^165638529531 is an apocalyptic number.

165638529531 is a deficient number, since it is larger than the sum of its proper divisors (90542032389).

165638529531 is a wasteful number, since it uses less digits than its factorization.

165638529531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126072 (or 126066 counting only the distinct ones).

The product of its digits is 5832000, while the sum is 54.

The spelling of 165638529531 in words is "one hundred sixty-five billion, six hundred thirty-eight million, five hundred twenty-nine thousand, five hundred thirty-one".