31312140 has 24 divisors (see below), whose sum is σ = 87674160. Its totient is φ = 8349888.

The previous prime is 31312123. The next prime is 31312157. The reversal of 31312140 is 4121313.

It is an interprime number because it is at equal distance from previous prime (31312123) and next prime (31312157).

It is a super-2 number, since 2×31312140² = 1960900222759200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

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 7 ways as a sum of consecutive naturals, for example, 260875 + ... + 260994.

It is an arithmetic number, because the mean of its divisors is an integer number (3653090).

Almost surely, 2^31312140 is an apocalyptic number.

31312140 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31312140 is an abundant number, since it is smaller than the sum of its proper divisors (56362020).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31312140 is a wasteful number, since it uses less digits than its factorization.

31312140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521881 (or 521879 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 31312140 is about 5595.7251540797. The cubic root of 31312140 is about 315.1889015607.

Adding to 31312140 its reverse (4121313), we get a palindrome (35433453).

The spelling of 31312140 in words is "thirty-one million, three hundred twelve thousand, one hundred forty".