521021957 has 2 divisors, whose sum is σ = 521021958. Its totient is φ = 521021956.

The previous prime is 521021953. The next prime is 521021989. The reversal of 521021957 is 759120125.

It is a happy number.

It is an a-pointer prime, because the next prime (521021989) can be obtained adding 521021957 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 519885601 + 1136356 = 22801^2 + 1066^2 .

It is a cyclic number.

It is not a de Polignac number, because 521021957 - 2² = 521021953 is a prime.

It is a super-2 number, since 2×521021957² = 542927759352219698, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (521021953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260510978 + 260510979.

It is an arithmetic number, because the mean of its divisors is an integer number (260510979).

Almost surely, 2^521021957 is an apocalyptic number.

It is an amenable number.

521021957 is a deficient number, since it is larger than the sum of its proper divisors (1).

521021957 is an equidigital number, since it uses as much as digits as its factorization.

521021957 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6300, while the sum is 32.

The square root of 521021957 is about 22825.9053927769. The cubic root of 521021957 is about 804.6716029941.

The spelling of 521021957 in words is "five hundred twenty-one million, twenty-one thousand, nine hundred fifty-seven".