31220440 has 32 divisors (see below), whose sum is σ = 71442000. Its totient is φ = 12275584.

The previous prime is 31220429. The next prime is 31220447. The reversal of 31220440 is 4402213.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31220447) 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, 4255 + ... + 8974.

Almost surely, 2^31220440 is an apocalyptic number.

It is an amenable number.

31220440 is an abundant number, since it is smaller than the sum of its proper divisors (40221560).

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

31220440 is a wasteful number, since it uses less digits than its factorization.

31220440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13299 (or 13295 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 31220440 is about 5587.5253914412. The cubic root of 31220440 is about 314.8809157658.

Adding to 31220440 its reverse (4402213), we get a palindrome (35622653).

The spelling of 31220440 in words is "thirty-one million, two hundred twenty thousand, four hundred forty".