31220000 has 120 divisors (see below), whose sum is σ = 88171776. Its totient is φ = 10656000.

The previous prime is 31219999. The next prime is 31220003. The reversal of 31220000 is 2213.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a self number, because there is not a number n which added to its sum of digits gives 31220000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31220003) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 139889 + ... + 140111.

Almost surely, 2^31220000 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 31220000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44085888).

31220000 is an abundant number, since it is smaller than the sum of its proper divisors (56951776).

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

31220000 is an equidigital number, since it uses as much as digits as its factorization.

31220000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 260 (or 237 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 8.

The square root of 31220000 is about 5587.4860178796. The cubic root of 31220000 is about 314.8794365185.

Adding to 31220000 its reverse (2213), we get a palindrome (31222213).

The spelling of 31220000 in words is "thirty-one million, two hundred twenty thousand".