21310212031 has 4 divisors (see below), whose sum is σ = 21311066392. Its totient is φ = 21309357672.

The previous prime is 21310212023. The next prime is 21310212059. The reversal of 21310212031 is 13021201312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21310212031 - 2³ = 21310212023 is a prime.

It is a super-2 number, since 2×21310212031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21310211996 and 21310212014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21310212731) 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 3 ways as a sum of consecutive naturals, for example, 388605 + ... + 440038.

It is an arithmetic number, because the mean of its divisors is an integer number (5327766598).

Almost surely, 2^21310212031 is an apocalyptic number.

21310212031 is a deficient number, since it is larger than the sum of its proper divisors (854361).

21310212031 is an equidigital number, since it uses as much as digits as its factorization.

21310212031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854360.

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21310212031 its reverse (13021201312), we get a palindrome (34331413343).

The spelling of 21310212031 in words is "twenty-one billion, three hundred ten million, two hundred twelve thousand, thirty-one".