400999999 has 2 divisors, whose sum is σ = 401000000. Its totient is φ = 400999998.

The previous prime is 400999993. The next prime is 401000011. The reversal of 400999999 is 999999004.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 400999999 - 2¹³ = 400991807 is a prime.

400999999 is a modest number, since divided by 99999 gives 4009 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400999993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200499999 + 200500000.

It is an arithmetic number, because the mean of its divisors is an integer number (200500000).

Almost surely, 2^400999999 is an apocalyptic number.

400999999 is a deficient number, since it is larger than the sum of its proper divisors (1).

400999999 is an equidigital number, since it uses as much as digits as its factorization.

400999999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2125764, while the sum is 58.

The square root of 400999999 is about 20024.9843695320. The cubic root of 400999999 is about 737.4197934033.

The spelling of 400999999 in words is "four hundred million, nine hundred ninety-nine thousand, nine hundred ninety-nine".