21157736293 has 2 divisors, whose sum is σ = 21157736294. Its totient is φ = 21157736292.

The previous prime is 21157736279. The next prime is 21157736329. The reversal of 21157736293 is 39263775112.

Together with next prime (21157736329) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20579910849 + 577825444 = 143457^2 + 24038^2 .

It is a cyclic number.

It is not a de Polignac number, because 21157736293 - 2²⁹ = 20620865381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21157736203) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10578868146 + 10578868147.

It is an arithmetic number, because the mean of its divisors is an integer number (10578868147).

Almost surely, 2^21157736293 is an apocalyptic number.

It is an amenable number.

21157736293 is a deficient number, since it is larger than the sum of its proper divisors (1).

21157736293 is an equidigital number, since it uses as much as digits as its factorization.

21157736293 is an evil number, because the sum of its binary digits is even.

The product of its digits is 476280, while the sum is 46.

The spelling of 21157736293 in words is "twenty-one billion, one hundred fifty-seven million, seven hundred thirty-six thousand, two hundred ninety-three".