31121020 has 24 divisors (see below), whose sum is σ = 74690784. Its totient is φ = 10670016.

The previous prime is 31120997. The next prime is 31121021. The reversal of 31121020 is 2012113.

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 = 31120988 and 31121006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31121021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111007 + ... + 111286.

It is an arithmetic number, because the mean of its divisors is an integer number (3112116).

Almost surely, 2^31121020 is an apocalyptic number.

It is an amenable number.

31121020 is an abundant number, since it is smaller than the sum of its proper divisors (43569764).

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

31121020 is a wasteful number, since it uses less digits than its factorization.

31121020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 222309 (or 222307 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 10.

The square root of 31121020 is about 5578.6216935727. The cubic root of 31121020 is about 314.5463192664.

Adding to 31121020 its reverse (2012113), we get a palindrome (33133133).

The spelling of 31121020 in words is "thirty-one million, one hundred twenty-one thousand, twenty".