31021010021 has 4 divisors (see below), whose sum is σ = 31023081792. Its totient is φ = 31018938252.

The previous prime is 31021010011. The next prime is 31021010023. The reversal of 31021010021 is 12001012013.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31021010021 - 2²² = 31016815717 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31021009984 and 31021010011.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31021010023) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1013261 + ... + 1043426.

It is an arithmetic number, because the mean of its divisors is an integer number (7755770448).

Almost surely, 2^31021010021 is an apocalyptic number.

It is an amenable number.

31021010021 is a deficient number, since it is larger than the sum of its proper divisors (2071771).

31021010021 is a wasteful number, since it uses less digits than its factorization.

31021010021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2071770.

The product of its (nonzero) digits is 12, while the sum is 11.

Adding to 31021010021 its reverse (12001012013), we get a palindrome (43022022034).

The spelling of 31021010021 in words is "thirty-one billion, twenty-one million, ten thousand, twenty-one".