402005521 has 2 divisors, whose sum is σ = 402005522. Its totient is φ = 402005520.

The previous prime is 402005509. The next prime is 402005543. The reversal of 402005521 is 125500204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 266864896 + 135140625 = 16336^2 + 11625^2 .

It is a cyclic number.

It is not a de Polignac number, because 402005521 - 2⁷ = 402005393 is a prime.

It is not a weakly prime, because it can be changed into another prime (402005321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201002760 + 201002761.

It is an arithmetic number, because the mean of its divisors is an integer number (201002761).

Almost surely, 2^402005521 is an apocalyptic number.

It is an amenable number.

402005521 is a deficient number, since it is larger than the sum of its proper divisors (1).

402005521 is an equidigital number, since it uses as much as digits as its factorization.

402005521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 400, while the sum is 19.

The square root of 402005521 is about 20050.0753365168. The cubic root of 402005521 is about 738.0356478645.

Adding to 402005521 its reverse (125500204), we get a palindrome (527505725).

The spelling of 402005521 in words is "four hundred two million, five thousand, five hundred twenty-one".