400991807 has 2 divisors, whose sum is σ = 400991808. Its totient is φ = 400991806.

The previous prime is 400991803. The next prime is 400991861. The reversal of 400991807 is 708199004.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 400991807 - 2² = 400991803 is a prime.

It is a super-2 number, since 2×400991807² = 321588858562250498, 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 (400991803) 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, 200495903 + 200495904.

It is an arithmetic number, because the mean of its divisors is an integer number (200495904).

Almost surely, 2^400991807 is an apocalyptic number.

400991807 is a deficient number, since it is larger than the sum of its proper divisors (1).

400991807 is an equidigital number, since it uses as much as digits as its factorization.

400991807 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18144, while the sum is 38.

The square root of 400991807 is about 20024.7798240081. The cubic root of 400991807 is about 737.4147718039.

The spelling of 400991807 in words is "four hundred million, nine hundred ninety-one thousand, eight hundred seven".