399243789 has 64 divisors (see below), whose sum is σ = 721766400. Its totient is φ = 213031296.

The previous prime is 399243787. The next prime is 399243791. The reversal of 399243789 is 987342993.

399243789 is a `hidden beast` number, since 399 + 243 + 7 + 8 + 9 = 666.

It is an interprime number because it is at equal distance from previous prime (399243787) and next prime (399243791).

It is not a de Polignac number, because 399243789 - 2¹ = 399243787 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399243787) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 261382 + ... + 262904.

It is an arithmetic number, because the mean of its divisors is an integer number (11277600).

Almost surely, 2^399243789 is an apocalyptic number.

It is an amenable number.

399243789 is a deficient number, since it is larger than the sum of its proper divisors (322522611).

399243789 is a wasteful number, since it uses less digits than its factorization.

399243789 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1631 (or 1625 counting only the distinct ones).

The product of its digits is 2939328, while the sum is 54.

The square root of 399243789 is about 19981.0857813083. The cubic root of 399243789 is about 736.3416892948.

The spelling of 399243789 in words is "three hundred ninety-nine million, two hundred forty-three thousand, seven hundred eighty-nine".