402568781 has 2 divisors, whose sum is σ = 402568782. Its totient is φ = 402568780.

The previous prime is 402568723. The next prime is 402568787. The reversal of 402568781 is 187865204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 395651881 + 6916900 = 19891^2 + 2630^2 .

It is a cyclic number.

It is not a de Polignac number, because 402568781 - 2²² = 398374477 is a prime.

It is a super-2 number, since 2×402568781² = 324123246871651922, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402568787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201284390 + 201284391.

It is an arithmetic number, because the mean of its divisors is an integer number (201284391).

Almost surely, 2^402568781 is an apocalyptic number.

It is an amenable number.

402568781 is a deficient number, since it is larger than the sum of its proper divisors (1).

402568781 is an equidigital number, since it uses as much as digits as its factorization.

402568781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 107520, while the sum is 41.

The square root of 402568781 is about 20064.1167510559. The cubic root of 402568781 is about 738.3801804113.

The spelling of 402568781 in words is "four hundred two million, five hundred sixty-eight thousand, seven hundred eighty-one".