402506521 has 2 divisors, whose sum is σ = 402506522. Its totient is φ = 402506520.

The previous prime is 402506497. The next prime is 402506551. The reversal of 402506521 is 125605204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 252174400 + 150332121 = 15880^2 + 12261^2 .

It is a cyclic number.

It is not a de Polignac number, because 402506521 - 2¹⁹ = 401982233 is a prime.

It is a super-2 number, since 2×402506521² = 324022998895046882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (402506551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201253260 + 201253261.

It is an arithmetic number, because the mean of its divisors is an integer number (201253261).

Almost surely, 2^402506521 is an apocalyptic number.

It is an amenable number.

402506521 is a deficient number, since it is larger than the sum of its proper divisors (1).

402506521 is an equidigital number, since it uses as much as digits as its factorization.

402506521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 402506521 is about 20062.5651650032. The cubic root of 402506521 is about 738.3421132765.

The spelling of 402506521 in words is "four hundred two million, five hundred six thousand, five hundred twenty-one".