402505309 has 2 divisors, whose sum is σ = 402505310. Its totient is φ = 402505308.

The previous prime is 402505303. The next prime is 402505349. The reversal of 402505309 is 903505204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 397882809 + 4622500 = 19947^2 + 2150^2 .

It is a cyclic number.

It is not a de Polignac number, because 402505309 - 2¹⁷ = 402374237 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402505303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201252654 + 201252655.

It is an arithmetic number, because the mean of its divisors is an integer number (201252655).

Almost surely, 2^402505309 is an apocalyptic number.

It is an amenable number.

402505309 is a deficient number, since it is larger than the sum of its proper divisors (1).

402505309 is an equidigital number, since it uses as much as digits as its factorization.

402505309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5400, while the sum is 28.

The square root of 402505309 is about 20062.5349594711. The cubic root of 402505309 is about 738.3413721941.

The spelling of 402505309 in words is "four hundred two million, five hundred five thousand, three hundred nine".