21013215031 has 2 divisors, whose sum is σ = 21013215032. Its totient is φ = 21013215030.

The previous prime is 21013215011. The next prime is 21013215037. The reversal of 21013215031 is 13051231012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21013215031 - 2²⁷ = 20878997303 is a prime.

It is a super-2 number, since 2×21013215031² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21013215037) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506607515 + 10506607516.

It is an arithmetic number, because the mean of its divisors is an integer number (10506607516).

Almost surely, 2^21013215031 is an apocalyptic number.

21013215031 is a deficient number, since it is larger than the sum of its proper divisors (1).

21013215031 is an equidigital number, since it uses as much as digits as its factorization.

21013215031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 180, while the sum is 19.

Adding to 21013215031 its reverse (13051231012), we get a palindrome (34064446043).

The spelling of 21013215031 in words is "twenty-one billion, thirteen million, two hundred fifteen thousand, thirty-one".