21352507613 has 2 divisors, whose sum is σ = 21352507614. Its totient is φ = 21352507612.

The previous prime is 21352507543. The next prime is 21352507633. The reversal of 21352507613 is 31670525312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20886897529 + 465610084 = 144523^2 + 21578^2 .

It is a cyclic number.

It is not a de Polignac number, because 21352507613 - 2¹⁰ = 21352506589 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21352507633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10676253806 + 10676253807.

It is an arithmetic number, because the mean of its divisors is an integer number (10676253807).

Almost surely, 2^21352507613 is an apocalyptic number.

It is an amenable number.

21352507613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21352507613 is an equidigital number, since it uses as much as digits as its factorization.

21352507613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 37800, while the sum is 35.

The spelling of 21352507613 in words is "twenty-one billion, three hundred fifty-two million, five hundred seven thousand, six hundred thirteen".