31506128 has 20 divisors (see below), whose sum is σ = 61141920. Its totient is φ = 15727584.

The previous prime is 31506119. The next prime is 31506149. The reversal of 31506128 is 82160513.

It is a super-2 number, since 2×31506128² = 1985272203104768, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 31506097 and 31506106.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12251 + ... + 14597.

It is an arithmetic number, because the mean of its divisors is an integer number (3057096).

Almost surely, 2^31506128 is an apocalyptic number.

It is an amenable number.

31506128 is a deficient number, since it is larger than the sum of its proper divisors (29635792).

31506128 is a wasteful number, since it uses less digits than its factorization.

31506128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3194 (or 3188 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 31506128 is about 5613.0319792426. The cubic root of 31506128 is about 315.8384582648.

The spelling of 31506128 in words is "thirty-one million, five hundred six thousand, one hundred twenty-eight".