403999961 has 2 divisors, whose sum is σ = 403999962. Its totient is φ = 403999960.

The previous prime is 403999949. The next prime is 403999969. The reversal of 403999961 is 169999304.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 310993225 + 93006736 = 17635^2 + 9644^2 .

It is a cyclic number.

It is not a de Polignac number, because 403999961 - 2¹⁴ = 403983577 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (403999969) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 201999980 + 201999981.

It is an arithmetic number, because the mean of its divisors is an integer number (201999981).

Almost surely, 2^403999961 is an apocalyptic number.

It is an amenable number.

403999961 is a deficient number, since it is larger than the sum of its proper divisors (1).

403999961 is an equidigital number, since it uses as much as digits as its factorization.

403999961 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 472392, while the sum is 50.

The square root of 403999961 is about 20099.7502720805. The cubic root of 403999961 is about 739.2541553835.

The spelling of 403999961 in words is "four hundred three million, nine hundred ninety-nine thousand, nine hundred sixty-one".