399400637 has 2 divisors, whose sum is σ = 399400638. Its totient is φ = 399400636.

The previous prime is 399400627. The next prime is 399400643. The reversal of 399400637 is 736004993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 214739716 + 184660921 = 14654^2 + 13589^2 .

It is a cyclic number.

It is not a de Polignac number, because 399400637 - 2⁸ = 399400381 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 399400594 and 399400603.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399400627) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199700318 + 199700319.

It is an arithmetic number, because the mean of its divisors is an integer number (199700319).

Almost surely, 2^399400637 is an apocalyptic number.

It is an amenable number.

399400637 is a deficient number, since it is larger than the sum of its proper divisors (1).

399400637 is an equidigital number, since it uses as much as digits as its factorization.

399400637 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 122472, while the sum is 41.

The square root of 399400637 is about 19985.0103077281. The cubic root of 399400637 is about 736.4381037357.

The spelling of 399400637 in words is "three hundred ninety-nine million, four hundred thousand, six hundred thirty-seven".