161566621631 has 8 divisors (see below), whose sum is σ = 163157658144. Its totient is φ = 159976016640.

The previous prime is 161566621597. The next prime is 161566621633. The reversal of 161566621631 is 136126665161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161566621631 - 2¹⁴ = 161566605247 is a prime.

It is a super-2 number, since 2×161566621631² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161566621633) 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, 672251 + ... + 880371.

It is an arithmetic number, because the mean of its divisors is an integer number (20394707268).

Almost surely, 2^161566621631 is an apocalyptic number.

161566621631 is a deficient number, since it is larger than the sum of its proper divisors (1591036513).

161566621631 is a wasteful number, since it uses less digits than its factorization.

161566621631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215761.

The product of its digits is 233280, while the sum is 44.

The spelling of 161566621631 in words is "one hundred sixty-one billion, five hundred sixty-six million, six hundred twenty-one thousand, six hundred thirty-one".