31687916121 has 63 divisors (see below), whose sum is σ = 50287199781. Its totient is φ = 19955745144.

The previous prime is 31687916087. The next prime is 31687916129. The reversal of 31687916121 is 12161978613.

The square root of 31687916121 is 178011.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 31687916121 - 2¹⁷ = 31687785049 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (31687916129) by changing a digit.

It is a polite number, since it can be written in 62 ways as a sum of consecutive naturals, for example, 91319470 + ... + 91319816.

Almost surely, 2^31687916121 is an apocalyptic number.

31687916121 is the 178011-st square number.

31687916121 is the 89006-th centered octagonal number.

It is an amenable number.

31687916121 is a deficient number, since it is larger than the sum of its proper divisors (18599283660).

31687916121 is an frugal number, since it uses more digits than its factorization.

31687916121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 750 (or 369 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The spelling of 31687916121 in words is "thirty-one billion, six hundred eighty-seven million, nine hundred sixteen thousand, one hundred twenty-one".