161566214231 has 4 divisors (see below), whose sum is σ = 161575552872. Its totient is φ = 161556875592.

The previous prime is 161566214213. The next prime is 161566214263. The reversal of 161566214231 is 132412665161.

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-161566214231 is a prime.

It is a super-2 number, since 2×161566214231² (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 (161566214431) 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, 4643321 + ... + 4677986.

It is an arithmetic number, because the mean of its divisors is an integer number (40393888218).

Almost surely, 2^161566214231 is an apocalyptic number.

161566214231 is a deficient number, since it is larger than the sum of its proper divisors (9338641).

161566214231 is an equidigital number, since it uses as much as digits as its factorization.

161566214231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9338640.

The product of its digits is 51840, while the sum is 38.

Adding to 161566214231 its reverse (132412665161), we get a palindrome (293978879392).

The spelling of 161566214231 in words is "one hundred sixty-one billion, five hundred sixty-six million, two hundred fourteen thousand, two hundred thirty-one".