31220928 has 84 divisors (see below), whose sum is σ = 90937080. Its totient is φ = 10238976.

The previous prime is 31220927. The next prime is 31220941. The reversal of 31220928 is 82902213.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (31220923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 38188 + ... + 38996.

Almost surely, 2^31220928 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 31220928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45468540).

31220928 is an abundant number, since it is smaller than the sum of its proper divisors (59716152).

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

31220928 is a wasteful number, since it uses less digits than its factorization.

31220928 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 894 (or 881 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 31220928 is about 5587.5690599759. The cubic root of 31220928 is about 314.8825563693.

The spelling of 31220928 in words is "thirty-one million, two hundred twenty thousand, nine hundred twenty-eight".