21320212993 has 2 divisors, whose sum is σ = 21320212994. Its totient is φ = 21320212992.

The previous prime is 21320212981. The next prime is 21320213003. The reversal of 21320212993 is 39921202312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13379086224 + 7941126769 = 115668^2 + 89113^2 .

It is a cyclic number.

It is not a de Polignac number, because 21320212993 - 2²⁹ = 20783342081 is a prime.

It is not a weakly prime, because it can be changed into another prime (21320212933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660106496 + 10660106497.

It is an arithmetic number, because the mean of its divisors is an integer number (10660106497).

Almost surely, 2^21320212993 is an apocalyptic number.

It is an amenable number.

21320212993 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320212993 is an equidigital number, since it uses as much as digits as its factorization.

21320212993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 34.

The spelling of 21320212993 in words is "twenty-one billion, three hundred twenty million, two hundred twelve thousand, nine hundred ninety-three".