399404787 has 4 divisors (see below), whose sum is σ = 532539720. Its totient is φ = 266269856.

The previous prime is 399404777. The next prime is 399404843. The reversal of 399404787 is 787404993.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 399404787 - 2⁶ = 399404723 is a prime.

It is not an unprimeable number, because it can be changed into a prime (399404717) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66567462 + ... + 66567467.

It is an arithmetic number, because the mean of its divisors is an integer number (133134930).

Almost surely, 2^399404787 is an apocalyptic number.

399404787 is a deficient number, since it is larger than the sum of its proper divisors (133134933).

399404787 is a wasteful number, since it uses less digits than its factorization.

399404787 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133134932.

The product of its (nonzero) digits is 1524096, while the sum is 51.

The square root of 399404787 is about 19985.1141352758. The cubic root of 399404787 is about 736.4406543973.

The spelling of 399404787 in words is "three hundred ninety-nine million, four hundred four thousand, seven hundred eighty-seven".