21152512457 has 2 divisors, whose sum is σ = 21152512458. Its totient is φ = 21152512456.

The previous prime is 21152512421. The next prime is 21152512501. The reversal of 21152512457 is 75421525112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10847014201 + 10305498256 = 104149^2 + 101516^2 .

It is a cyclic number.

It is not a de Polignac number, because 21152512457 - 2¹² = 21152508361 is a prime.

It is not a weakly prime, because it can be changed into another prime (21152512057) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10576256228 + 10576256229.

It is an arithmetic number, because the mean of its divisors is an integer number (10576256229).

Almost surely, 2^21152512457 is an apocalyptic number.

It is an amenable number.

21152512457 is a deficient number, since it is larger than the sum of its proper divisors (1).

21152512457 is an equidigital number, since it uses as much as digits as its factorization.

21152512457 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28000, while the sum is 35.

The spelling of 21152512457 in words is "twenty-one billion, one hundred fifty-two million, five hundred twelve thousand, four hundred fifty-seven".