400128637 has 2 divisors, whose sum is σ = 400128638. Its totient is φ = 400128636.

The previous prime is 400128629. The next prime is 400128653. The reversal of 400128637 is 736821004.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 399560121 + 568516 = 19989^2 + 754^2 .

It is a cyclic number.

It is not a de Polignac number, because 400128637 - 2³ = 400128629 is a prime.

It is a super-2 number, since 2×400128637² = 320205852294955538, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 400128599 and 400128608.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (400128137) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 200064318 + 200064319.

It is an arithmetic number, because the mean of its divisors is an integer number (200064319).

Almost surely, 2^400128637 is an apocalyptic number.

It is an amenable number.

400128637 is a deficient number, since it is larger than the sum of its proper divisors (1).

400128637 is an equidigital number, since it uses as much as digits as its factorization.

400128637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8064, while the sum is 31.

The square root of 400128637 is about 20003.2156664872. The cubic root of 400128637 is about 736.8852750560.

The spelling of 400128637 in words is "four hundred million, one hundred twenty-eight thousand, six hundred thirty-seven".