400128857 has 2 divisors, whose sum is σ = 400128858. Its totient is φ = 400128856.

The previous prime is 400128793. The next prime is 400128877. The reversal of 400128857 is 758821004.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 219602761 + 180526096 = 14819^2 + 13436^2 .

It is a cyclic number.

It is not a de Polignac number, because 400128857 - 2⁶ = 400128793 is a prime.

It is not a weakly prime, because it can be changed into another prime (400128877) 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, 200064428 + 200064429.

It is an arithmetic number, because the mean of its divisors is an integer number (200064429).

Almost surely, 2^400128857 is an apocalyptic number.

It is an amenable number.

400128857 is a deficient number, since it is larger than the sum of its proper divisors (1).

400128857 is an equidigital number, since it uses as much as digits as its factorization.

400128857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 400128857 is about 20003.2211656023. The cubic root of 400128857 is about 736.8854101082.

The spelling of 400128857 in words is "four hundred million, one hundred twenty-eight thousand, eight hundred fifty-seven".