399787457 has 2 divisors, whose sum is σ = 399787458. Its totient is φ = 399787456.

The previous prime is 399787387. The next prime is 399787463. The reversal of 399787457 is 754787993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 261113281 + 138674176 = 16159^2 + 11776^2 .

It is a cyclic number.

It is not a de Polignac number, because 399787457 - 2²⁰ = 398738881 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 399787396 and 399787405.

It is not a weakly prime, because it can be changed into another prime (399787477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199893728 + 199893729.

It is an arithmetic number, because the mean of its divisors is an integer number (199893729).

Almost surely, 2^399787457 is an apocalyptic number.

It is an amenable number.

399787457 is a deficient number, since it is larger than the sum of its proper divisors (1).

399787457 is an equidigital number, since it uses as much as digits as its factorization.

399787457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13335840, while the sum is 59.

The square root of 399787457 is about 19994.6857189604. The cubic root of 399787457 is about 736.6757740890.

The spelling of 399787457 in words is "three hundred ninety-nine million, seven hundred eighty-seven thousand, four hundred fifty-seven".