525817520021 has 2 divisors, whose sum is σ = 525817520022. Its totient is φ = 525817520020.

The previous prime is 525817520003. The next prime is 525817520087. The reversal of 525817520021 is 120025718525.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 509717463025 + 16100056996 = 713945^2 + 126886^2 .

It is a cyclic number.

It is not a de Polignac number, because 525817520021 - 2¹⁸ = 525817257877 is a prime.

It is a super-2 number, since 2×525817520021² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (525817526021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 262908760010 + 262908760011.

It is an arithmetic number, because the mean of its divisors is an integer number (262908760011).

Almost surely, 2^525817520021 is an apocalyptic number.

It is an amenable number.

525817520021 is a deficient number, since it is larger than the sum of its proper divisors (1).

525817520021 is an equidigital number, since it uses as much as digits as its factorization.

525817520021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 56000, while the sum is 38.

The spelling of 525817520021 in words is "five hundred twenty-five billion, eight hundred seventeen million, five hundred twenty thousand, twenty-one".