31220856 has 32 divisors (see below), whose sum is σ = 86725200. Its totient is φ = 10406880.

The previous prime is 31220851. The next prime is 31220873. The reversal of 31220856 is 65802213.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31220851) by changing a digit.

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, 72055 + ... + 72486.

Almost surely, 2^31220856 is an apocalyptic number.

31220856 is a gapful number since it is divisible by the number (36) formed by its first and last digit.

It is an amenable number.

31220856 is an abundant number, since it is smaller than the sum of its proper divisors (55504344).

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

31220856 is a wasteful number, since it uses less digits than its factorization.

31220856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144556 (or 144546 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 27.

The square root of 31220856 is about 5587.5626170988. The cubic root of 31220856 is about 314.8823143141.

The spelling of 31220856 in words is "thirty-one million, two hundred twenty thousand, eight hundred fifty-six".