402890861 has 2 divisors, whose sum is σ = 402890862. Its totient is φ = 402890860.

The previous prime is 402890857. The next prime is 402890927. The reversal of 402890861 is 168098204.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 383924836 + 18966025 = 19594^2 + 4355^2 .

It is a cyclic number.

It is not a de Polignac number, because 402890861 - 2² = 402890857 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (402890461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201445430 + 201445431.

It is an arithmetic number, because the mean of its divisors is an integer number (201445431).

Almost surely, 2^402890861 is an apocalyptic number.

It is an amenable number.

402890861 is a deficient number, since it is larger than the sum of its proper divisors (1).

402890861 is an equidigital number, since it uses as much as digits as its factorization.

402890861 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 38.

The square root of 402890861 is about 20072.1414154046. The cubic root of 402890861 is about 738.5770445705.

The spelling of 402890861 in words is "four hundred two million, eight hundred ninety thousand, eight hundred sixty-one".