21206057513489 has 2 divisors, whose sum is σ = 21206057513490. Its totient is φ = 21206057513488.

The previous prime is 21206057513383. The next prime is 21206057513561. The reversal of 21206057513489 is 98431575060212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21192994852225 + 13062661264 = 4603585^2 + 114292^2 .

It is a cyclic number.

It is not a de Polignac number, because 21206057513489 - 2³² = 21201762546193 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21206057513489.

It is not a weakly prime, because it can be changed into another prime (21206057510489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10603028756744 + 10603028756745.

It is an arithmetic number, because the mean of its divisors is an integer number (10603028756745).

It is a 1-persistent number, because it is pandigital, but 2⋅21206057513489 = 42412115026978 is not.

Almost surely, 2^{21206057513489} is an apocalyptic number.

It is an amenable number.

21206057513489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21206057513489 is an equidigital number, since it uses as much as digits as its factorization.

21206057513489 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3628800, while the sum is 53.

The spelling of 21206057513489 in words is "twenty-one trillion, two hundred six billion, fifty-seven million, five hundred thirteen thousand, four hundred eighty-nine".