31220402220 has 144 divisors (see below), whose sum is σ = 109242701568. Its totient is φ = 7069368960.

The previous prime is 31220402189. The next prime is 31220402231. The reversal of 31220402220 is 2220402213.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 31220402193 and 31220402202.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 19035 + ... + 250605.

It is an arithmetic number, because the mean of its divisors is an integer number (758629872).

Almost surely, 2^31220402220 is an apocalyptic number.

31220402220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31220402220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (54621350784).

31220402220 is an abundant number, since it is smaller than the sum of its proper divisors (78022299348).

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

31220402220 is a wasteful number, since it uses less digits than its factorization.

31220402220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 231700 (or 231695 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 18.

Adding to 31220402220 its reverse (2220402213), we get a palindrome (33440804433).

The spelling of 31220402220 in words is "thirty-one billion, two hundred twenty million, four hundred two thousand, two hundred twenty".