31213056 has 80 divisors (see below), whose sum is σ = 95065344. Its totient is φ = 8914944.

The previous prime is 31213051. The next prime is 31213069. The reversal of 31213056 is 65031213.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31213051) 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, 9301 + ... + 12203.

Almost surely, 2^31213056 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31213056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47532672).

31213056 is an abundant number, since it is smaller than the sum of its proper divisors (63852288).

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

31213056 is an equidigital number, since it uses as much as digits as its factorization.

31213056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2931 (or 2915 counting only the distinct ones).

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 31213056 is about 5586.8645947436. The cubic root of 31213056 is about 314.8560894660.

Adding to 31213056 its reverse (65031213), we get a palindrome (96244269).

The spelling of 31213056 in words is "thirty-one million, two hundred thirteen thousand, fifty-six".