21310031011 has 4 divisors (see below), whose sum is σ = 21313070632. Its totient is φ = 21306991392.

The previous prime is 21310030999. The next prime is 21310031023. The reversal of 21310031011 is 11013001312.

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

It is an interprime number because it is at equal distance from previous prime (21310030999) and next prime (21310031023).

It is a cyclic number.

It is not a de Polignac number, because 21310031011 - 2⁹ = 21310030499 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21310030982 and 21310031000.

It is not an unprimeable number, because it can be changed into a prime (21310031051) 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 3 ways as a sum of consecutive naturals, for example, 1509270 + ... + 1523323.

It is an arithmetic number, because the mean of its divisors is an integer number (5328267658).

Almost surely, 2^21310031011 is an apocalyptic number.

21310031011 is a deficient number, since it is larger than the sum of its proper divisors (3039621).

21310031011 is an equidigital number, since it uses as much as digits as its factorization.

21310031011 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3039620.

The product of its (nonzero) digits is 18, while the sum is 13.

Adding to 21310031011 its reverse (11013001312), we get a palindrome (32323032323).

The spelling of 21310031011 in words is "twenty-one billion, three hundred ten million, thirty-one thousand, eleven".