31181517949972 has 24 divisors (see below), whose sum is σ = 58770135814376. Its totient is φ = 14390253324288.

The previous prime is 31181517949957. The next prime is 31181517949979. The reversal of 31181517949972 is 27994971518113.

It can be written as a sum of positive squares in 4 ways, for example, as 3450804077956 + 27730713872016 = 1857634^2 + 5265996^2 .

It is a junction number, because it is equal to n+sod(n) for n = 31181517949898 and 31181517949907.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31181517949979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24722493 + ... + 25953124.

Almost surely, 2^{31181517949972} is an apocalyptic number.

It is an amenable number.

31181517949972 is a deficient number, since it is larger than the sum of its proper divisors (27588617864404).

31181517949972 is a wasteful number, since it uses less digits than its factorization.

31181517949972 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50687467 (or 50687465 counting only the distinct ones).

The product of its digits is 34292160, while the sum is 67.

The spelling of 31181517949972 in words is "thirty-one trillion, one hundred eighty-one billion, five hundred seventeen million, nine hundred forty-nine thousand, nine hundred seventy-two".