31313220021 has 24 divisors (see below), whose sum is σ = 45531682560. Its totient is φ = 20736746496.

The previous prime is 31313220007. The next prime is 31313220041. The reversal of 31313220021 is 12002231313.

31313220021 is a `hidden beast` number, since 313 + 132 + 200 + 21 = 666.

It is not a de Polignac number, because 31313220021 - 2¹⁰ = 31313218997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 31313219976 and 31313220003.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31313220041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 920565 + ... + 953973.

It is an arithmetic number, because the mean of its divisors is an integer number (1897153440).

Almost surely, 2^31313220021 is an apocalyptic number.

It is an amenable number.

31313220021 is a deficient number, since it is larger than the sum of its proper divisors (14218462539).

31313220021 is a wasteful number, since it uses less digits than its factorization.

31313220021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34105 (or 34102 counting only the distinct ones).

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

Adding to 31313220021 its reverse (12002231313), we get a palindrome (43315451334).

The spelling of 31313220021 in words is "thirty-one billion, three hundred thirteen million, two hundred twenty thousand, twenty-one".