31131681 has 8 divisors (see below), whose sum is σ = 47438784. Its totient is φ = 17789520.

The previous prime is 31131679. The next prime is 31131701. The reversal of 31131681 is 18613113.

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

It is not a de Polignac number, because 31131681 - 2¹ = 31131679 is a prime.

It is a super-2 number, since 2×31131681² = 1938363123771522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (31131601) 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, 741210 + ... + 741251.

It is an arithmetic number, because the mean of its divisors is an integer number (5929848).

Almost surely, 2^31131681 is an apocalyptic number.

It is an amenable number.

31131681 is a deficient number, since it is larger than the sum of its proper divisors (16307103).

31131681 is a wasteful number, since it uses less digits than its factorization.

31131681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1482471.

The product of its digits is 432, while the sum is 24.

The square root of 31131681 is about 5579.5771345148. The cubic root of 31131681 is about 314.5822327793.

Adding to 31131681 its reverse (18613113), we get a palindrome (49744794).

The spelling of 31131681 in words is "thirty-one million, one hundred thirty-one thousand, six hundred eighty-one".