21247157593 has 2 divisors, whose sum is σ = 21247157594. Its totient is φ = 21247157592.

The previous prime is 21247157567. The next prime is 21247157621. The reversal of 21247157593 is 39575174212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11609416009 + 9637741584 = 107747^2 + 98172^2 .

It is a cyclic number.

It is not a de Polignac number, because 21247157593 - 2³³ = 12657223001 is a prime.

It is not a weakly prime, because it can be changed into another prime (21247157513) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10623578796 + 10623578797.

It is an arithmetic number, because the mean of its divisors is an integer number (10623578797).

Almost surely, 2^21247157593 is an apocalyptic number.

It is an amenable number.

21247157593 is a deficient number, since it is larger than the sum of its proper divisors (1).

21247157593 is an equidigital number, since it uses as much as digits as its factorization.

21247157593 is an evil number, because the sum of its binary digits is even.

The product of its digits is 529200, while the sum is 46.

The spelling of 21247157593 in words is "twenty-one billion, two hundred forty-seven million, one hundred fifty-seven thousand, five hundred ninety-three".