402661309 has 4 divisors (see below), whose sum is σ = 403215904. Its totient is φ = 402106716.

The previous prime is 402661289. The next prime is 402661313. The reversal of 402661309 is 903166204.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 402661309 - 2⁵ = 402661277 is a prime.

It is a super-2 number, since 2×402661309² = 324272259531186962, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (402661379) 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 in 3 ways as a sum of consecutive naturals, for example, 276207 + ... + 277660.

It is an arithmetic number, because the mean of its divisors is an integer number (100803976).

Almost surely, 2^402661309 is an apocalyptic number.

It is an amenable number.

402661309 is a deficient number, since it is larger than the sum of its proper divisors (554595).

402661309 is an equidigital number, since it uses as much as digits as its factorization.

402661309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 554594.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 402661309 is about 20066.4224265313. The cubic root of 402661309 is about 738.4367468176.

The spelling of 402661309 in words is "four hundred two million, six hundred sixty-one thousand, three hundred nine".