400866779 has 2 divisors, whose sum is σ = 400866780. Its totient is φ = 400866778.

The previous prime is 400866761. The next prime is 400866803. The reversal of 400866779 is 977668004.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-400866779 is a prime.

It is not a weakly prime, because it can be changed into another prime (400866679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200433389 + 200433390.

It is an arithmetic number, because the mean of its divisors is an integer number (200433390).

Almost surely, 2^400866779 is an apocalyptic number.

400866779 is a deficient number, since it is larger than the sum of its proper divisors (1).

400866779 is an equidigital number, since it uses as much as digits as its factorization.

400866779 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 508032, while the sum is 47.

The square root of 400866779 is about 20021.6577485482. The cubic root of 400866779 is about 737.3381226252.

The spelling of 400866779 in words is "four hundred million, eight hundred sixty-six thousand, seven hundred seventy-nine".