21457540613 has 2 divisors, whose sum is σ = 21457540614. Its totient is φ = 21457540612.

The previous prime is 21457540603. The next prime is 21457540619. The reversal of 21457540613 is 31604575412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17208717124 + 4248823489 = 131182^2 + 65183^2 .

It is a cyclic number.

It is not a de Polignac number, because 21457540613 - 2⁶ = 21457540549 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21457540619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10728770306 + 10728770307.

It is an arithmetic number, because the mean of its divisors is an integer number (10728770307).

Almost surely, 2^21457540613 is an apocalyptic number.

It is an amenable number.

21457540613 is a deficient number, since it is larger than the sum of its proper divisors (1).

21457540613 is an equidigital number, since it uses as much as digits as its factorization.

21457540613 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 100800, while the sum is 38.

The spelling of 21457540613 in words is "twenty-one billion, four hundred fifty-seven million, five hundred forty thousand, six hundred thirteen".