31220418 has 16 divisors (see below), whose sum is σ = 62536320. Its totient is φ = 10390896.

The previous prime is 31220383. The next prime is 31220419. The reversal of 31220418 is 81402213.

It is a junction number, because it is equal to n+sod(n) for n = 31220394 and 31220403.

It is not an unprimeable number, because it can be changed into a prime (31220419) 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, 696 + ... + 7932.

It is an arithmetic number, because the mean of its divisors is an integer number (3908520).

Almost surely, 2^31220418 is an apocalyptic number.

31220418 is an abundant number, since it is smaller than the sum of its proper divisors (31315902).

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

31220418 is a wasteful number, since it uses less digits than its factorization.

31220418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7961.

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 31220418 is about 5587.5234227697. The cubic root of 31220418 is about 314.8808418038.

The spelling of 31220418 in words is "thirty-one million, two hundred twenty thousand, four hundred eighteen".