402740309 has 2 divisors, whose sum is σ = 402740310. Its totient is φ = 402740308.

The previous prime is 402740257. The next prime is 402740311. The reversal of 402740309 is 903047204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 397803025 + 4937284 = 19945^2 + 2222^2 .

It is a cyclic number.

It is not a de Polignac number, because 402740309 - 2²⁸ = 134304853 is a prime.

It is a Sophie Germain prime.

Together with 402740311, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402740339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201370154 + 201370155.

It is an arithmetic number, because the mean of its divisors is an integer number (201370155).

Almost surely, 2^402740309 is an apocalyptic number.

It is an amenable number.

402740309 is a deficient number, since it is larger than the sum of its proper divisors (1).

402740309 is an equidigital number, since it uses as much as digits as its factorization.

402740309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 402740309 is about 20068.3907924876. The cubic root of 402740309 is about 738.4850361093.

The spelling of 402740309 in words is "four hundred two million, seven hundred forty thousand, three hundred nine".