165631661526451 has 4 divisors (see below), whose sum is σ = 165752296386912. Its totient is φ = 165511026665992.

The previous prime is 165631661526437. The next prime is 165631661526473. The reversal of 165631661526451 is 154625166136561.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165631661526451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165631661526431) 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, 60317428171 + ... + 60317430916.

It is an arithmetic number, because the mean of its divisors is an integer number (41438074096728).

Almost surely, 2^{165631661526451} is an apocalyptic number.

165631661526451 is a deficient number, since it is larger than the sum of its proper divisors (120634860461).

165631661526451 is a wasteful number, since it uses less digits than its factorization.

165631661526451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120634860460.

The product of its digits is 23328000, while the sum is 58.

The spelling of 165631661526451 in words is "one hundred sixty-five trillion, six hundred thirty-one billion, six hundred sixty-one million, five hundred twenty-six thousand, four hundred fifty-one".