399656656993 has 16 divisors (see below), whose sum is σ = 455227641216. Its totient is φ = 347311719040.

The previous prime is 399656656991. The next prime is 399656656999.

It is a happy number.

399656656993 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 399656656993 - 2¹ = 399656656991 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399656656991) 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, 81580 + ... + 897757.

It is an arithmetic number, because the mean of its divisors is an integer number (28451727576).

Almost surely, 2^399656656993 is an apocalyptic number.

It is an amenable number.

399656656993 is a deficient number, since it is larger than the sum of its proper divisors (55570984223).

399656656993 is a wasteful number, since it uses less digits than its factorization.

399656656993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 980984.

The product of its digits is 1913187600, while the sum is 76.

The spelling of 399656656993 in words is "three hundred ninety-nine billion, six hundred fifty-six million, six hundred fifty-six thousand, nine hundred ninety-three".