31130020 has 12 divisors (see below), whose sum is σ = 65373084. Its totient is φ = 12452000.

The previous prime is 31129991. The next prime is 31130039. The reversal of 31130020 is 2003113.

It can be written as a sum of positive squares in 2 ways, for example, as 4359744 + 26770276 = 2088^2 + 5174^2 .

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a junction number, because it is equal to n+sod(n) for n = 31129979 and 31130006.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 778231 + ... + 778270.

It is an arithmetic number, because the mean of its divisors is an integer number (5447757).

Almost surely, 2^31130020 is an apocalyptic number.

It is an amenable number.

31130020 is an abundant number, since it is smaller than the sum of its proper divisors (34243064).

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

31130020 is a wasteful number, since it uses less digits than its factorization.

31130020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556510 (or 1556508 counting only the distinct ones).

The product of its (nonzero) digits is 18, while the sum is 10.

The square root of 31130020 is about 5579.4282861239. The cubic root of 31130020 is about 314.5766379387.

Adding to 31130020 its reverse (2003113), we get a palindrome (33133133).

The spelling of 31130020 in words is "thirty-one million, one hundred thirty thousand, twenty".