31660020 has 72 divisors (see below), whose sum is σ = 109759104. Its totient is φ = 7236288.

The previous prime is 31660003. The next prime is 31660033. The reversal of 31660020 is 2006613.

It is a happy number.

31660020 is a `hidden beast` number, since 3 + 1 + 660 + 0 + 2 + 0 = 666.

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 = 31659975 and 31660002.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11304 + ... + 13823.

It is an arithmetic number, because the mean of its divisors is an integer number (1524432).

Almost surely, 2^31660020 is an apocalyptic number.

31660020 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31660020 is an abundant number, since it is smaller than the sum of its proper divisors (78099084).

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

31660020 is a wasteful number, since it uses less digits than its factorization.

31660020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25149 (or 25144 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 18.

The square root of 31660020 is about 5626.7237358875. The cubic root of 31660020 is about 316.3518619731.

Adding to 31660020 its reverse (2006613), we get a palindrome (33666633).

The spelling of 31660020 in words is "thirty-one million, six hundred sixty thousand, twenty".