31680020 has 12 divisors (see below), whose sum is σ = 66528084. Its totient is φ = 12672000.

The previous prime is 31680007. The next prime is 31680031. The reversal of 31680020 is 2008613.

It can be written as a sum of positive squares in 2 ways, for example, as 15147664 + 16532356 = 3892^2 + 4066^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 1584001 = 31680020 / (3 + 1 + 6 + 8 + 0 + 0 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 31679974 and 31680001.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 791981 + ... + 792020.

It is an arithmetic number, because the mean of its divisors is an integer number (5544007).

Almost surely, 2^31680020 is an apocalyptic number.

It is an amenable number.

31680020 is an abundant number, since it is smaller than the sum of its proper divisors (34848064).

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

31680020 is a wasteful number, since it uses less digits than its factorization.

31680020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1584010 (or 1584008 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 31680020 is about 5628.5006884605. The cubic root of 31680020 is about 316.4184623250.

Adding to 31680020 its reverse (2008613), we get a palindrome (33688633).

The spelling of 31680020 in words is "thirty-one million, six hundred eighty thousand, twenty".