399638537 has 2 divisors, whose sum is σ = 399638538. Its totient is φ = 399638536.

The previous prime is 399638513. The next prime is 399638557. The reversal of 399638537 is 735836993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212605561 + 187032976 = 14581^2 + 13676^2 .

It is a cyclic number.

It is not a de Polignac number, because 399638537 - 2¹² = 399634441 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (399638557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199819268 + 199819269.

It is an arithmetic number, because the mean of its divisors is an integer number (199819269).

Almost surely, 2^399638537 is an apocalyptic number.

It is an amenable number.

399638537 is a deficient number, since it is larger than the sum of its proper divisors (1).

399638537 is an equidigital number, since it uses as much as digits as its factorization.

399638537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3674160, while the sum is 53.

The square root of 399638537 is about 19990.9613825849. The cubic root of 399638537 is about 736.5842926623.

The spelling of 399638537 in words is "three hundred ninety-nine million, six hundred thirty-eight thousand, five hundred thirty-seven".