400400399987 has 16 divisors (see below), whose sum is σ = 468851496960. Its totient is φ = 334782830592.

The previous prime is 400400399939. The next prime is 400400400007. The reversal of 400400399987 is 789993004004.

It is a happy number.

It is not a de Polignac number, because 400400399987 - 2³² = 396105432691 is a prime.

It is not an unprimeable number, because it can be changed into a prime (400400390987) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 633443 + ... + 1096380.

It is an arithmetic number, because the mean of its divisors is an integer number (29303218560).

Almost surely, 2^400400399987 is an apocalyptic number.

400400399987 is a deficient number, since it is larger than the sum of its proper divisors (68451096973).

400400399987 is a wasteful number, since it uses less digits than its factorization.

400400399987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1730642.

The product of its (nonzero) digits is 1959552, while the sum is 53.

The spelling of 400400399987 in words is "four hundred billion, four hundred million, three hundred ninety-nine thousand, nine hundred eighty-seven".