400128757 has 24 divisors (see below), whose sum is σ = 475135584. Its totient is φ = 335899872.

The previous prime is 400128731. The next prime is 400128793. The reversal of 400128757 is 757821004.

It is a happy number.

It is not a de Polignac number, because 400128757 - 2⁷ = 400128629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400128727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1007683 + ... + 1008079.

It is an arithmetic number, because the mean of its divisors is an integer number (19797316).

Almost surely, 2^400128757 is an apocalyptic number.

It is an amenable number.

400128757 is a deficient number, since it is larger than the sum of its proper divisors (75006827).

400128757 is a wasteful number, since it uses less digits than its factorization.

400128757 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785 (or 778 counting only the distinct ones).

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 400128757 is about 20003.2186660047. The cubic root of 400128757 is about 736.8853487209.

The spelling of 400128757 in words is "four hundred million, one hundred twenty-eight thousand, seven hundred fifty-seven".