31681929 has 4 divisors (see below), whose sum is σ = 42242576. Its totient is φ = 21121284.

The previous prime is 31681913. The next prime is 31681939. The reversal of 31681929 is 92918613.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 92918613 = 3 ⋅30972871.

It is not a de Polignac number, because 31681929 - 2⁴ = 31681913 is a prime.

It is a super-2 number, since 2×31681929² = 2007489250322082, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31681939) 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, 5280319 + ... + 5280324.

It is an arithmetic number, because the mean of its divisors is an integer number (10560644).

Almost surely, 2^31681929 is an apocalyptic number.

It is an amenable number.

31681929 is a deficient number, since it is larger than the sum of its proper divisors (10560647).

31681929 is a wasteful number, since it uses less digits than its factorization.

31681929 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10560646.

The product of its digits is 23328, while the sum is 39.

The square root of 31681929 is about 5628.6702692554. The cubic root of 31681929 is about 316.4248178629.

The spelling of 31681929 in words is "thirty-one million, six hundred eighty-one thousand, nine hundred twenty-nine".