21256020610597 has 2 divisors, whose sum is σ = 21256020610598. Its totient is φ = 21256020610596.

The previous prime is 21256020610441. The next prime is 21256020610661. The reversal of 21256020610597 is 79501602065212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20066941588996 + 1189079021601 = 4479614^2 + 1090449^2 .

It is a cyclic number.

It is not a de Polignac number, because 21256020610597 - 2¹⁹ = 21256020086309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21256020610997) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10628010305298 + 10628010305299.

It is an arithmetic number, because the mean of its divisors is an integer number (10628010305299).

Almost surely, 2^{21256020610597} is an apocalyptic number.

It is an amenable number.

21256020610597 is a deficient number, since it is larger than the sum of its proper divisors (1).

21256020610597 is an equidigital number, since it uses as much as digits as its factorization.

21256020610597 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 453600, while the sum is 46.

The spelling of 21256020610597 in words is "twenty-one trillion, two hundred fifty-six billion, twenty million, six hundred ten thousand, five hundred ninety-seven".