399387816651 has 16 divisors (see below), whose sum is σ = 534592194560. Its totient is φ = 265221397440.

The previous prime is 399387816649. The next prime is 399387816673. The reversal of 399387816651 is 156618783993.

It is not a de Polignac number, because 399387816651 - 2¹ = 399387816649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399387816151) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4108830 + ... + 4204908.

It is an arithmetic number, because the mean of its divisors is an integer number (33412012160).

Almost surely, 2^399387816651 is an apocalyptic number.

399387816651 is a deficient number, since it is larger than the sum of its proper divisors (135204377909).

399387816651 is a wasteful number, since it uses less digits than its factorization.

399387816651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101466.

The product of its digits is 58786560, while the sum is 66.

The spelling of 399387816651 in words is "three hundred ninety-nine billion, three hundred eighty-seven million, eight hundred sixteen thousand, six hundred fifty-one".