165871187038531 has 4 divisors (see below), whose sum is σ = 178630509118432. Its totient is φ = 153111864958632.

The previous prime is 165871187038519. The next prime is 165871187038573. The reversal of 165871187038531 is 135830781178561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 165871187038531 - 2²¹ = 165871184941379 is a prime.

It is a super-2 number, since 2×165871187038531² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165871187038231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6379661039931 + ... + 6379661039956.

It is an arithmetic number, because the mean of its divisors is an integer number (44657627279608).

Almost surely, 2^{165871187038531} is an apocalyptic number.

165871187038531 is a deficient number, since it is larger than the sum of its proper divisors (12759322079901).

165871187038531 is a wasteful number, since it uses less digits than its factorization.

165871187038531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12759322079900.

The product of its (nonzero) digits is 33868800, while the sum is 64.

The spelling of 165871187038531 in words is "one hundred sixty-five trillion, eight hundred seventy-one billion, one hundred eighty-seven million, thirty-eight thousand, five hundred thirty-one".