400128939 has 12 divisors (see below), whose sum is σ = 660530416. Its totient is φ = 228645072.

The previous prime is 400128931. The next prime is 400128943. The reversal of 400128939 is 939821004.

It is not a de Polignac number, because 400128939 - 2³ = 400128931 is a prime.

It is not an unprimeable number, because it can be changed into a prime (400128931) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3175564 + ... + 3175689.

Almost surely, 2^400128939 is an apocalyptic number.

400128939 is a deficient number, since it is larger than the sum of its proper divisors (260401477).

400128939 is a wasteful number, since it uses less digits than its factorization.

400128939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6351266 (or 6351263 counting only the distinct ones).

The product of its (nonzero) digits is 15552, while the sum is 36.

The square root of 400128939 is about 20003.2232152721. The cubic root of 400128939 is about 736.8854604458.

The spelling of 400128939 in words is "four hundred million, one hundred twenty-eight thousand, nine hundred thirty-nine".