31220220 has 48 divisors (see below), whose sum is σ = 89284608. Its totient is φ = 8147520.

The previous prime is 31220219. The next prime is 31220239. The reversal of 31220220 is 2202213.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 31220196 and 31220205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2716 + ... + 8355.

It is an arithmetic number, because the mean of its divisors is an integer number (1860096).

Almost surely, 2^31220220 is an apocalyptic number.

31220220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31220220 is an abundant number, since it is smaller than the sum of its proper divisors (58064388).

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

31220220 is a wasteful number, since it uses less digits than its factorization.

31220220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11130 (or 11128 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 12.

The square root of 31220220 is about 5587.5057046951. The cubic root of 31220220 is about 314.8801761439.

Adding to 31220220 its reverse (2202213), we get a palindrome (33422433).

The spelling of 31220220 in words is "thirty-one million, two hundred twenty thousand, two hundred twenty".