400043987 has 16 divisors (see below), whose sum is σ = 467486400. Its totient is φ = 342187776.

The previous prime is 400043977. The next prime is 400043999. The reversal of 400043987 is 789340004.

It is not a de Polignac number, because 400043987 - 2⁴ = 400043971 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (400043977) 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, 229973 + ... + 231705.

It is an arithmetic number, because the mean of its divisors is an integer number (29217900).

Almost surely, 2^400043987 is an apocalyptic number.

400043987 is a deficient number, since it is larger than the sum of its proper divisors (67442413).

400043987 is an equidigital number, since it uses as much as digits as its factorization.

400043987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2427 (or 2413 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 35.

The square root of 400043987 is about 20001.0996447695. The cubic root of 400043987 is about 736.8333069870.

The spelling of 400043987 in words is "four hundred million, forty-three thousand, nine hundred eighty-seven".