399668386553 has 4 divisors (see below), whose sum is σ = 400453590180. Its totient is φ = 398883182928.

The previous prime is 399668386549. The next prime is 399668386567. The reversal of 399668386553 is 355683866993.

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

It can be written as a sum of positive squares in 2 ways, for example, as 322491101689 + 77177284864 = 567883^2 + 277808^2 .

It is a cyclic number.

It is not a de Polignac number, because 399668386553 - 2² = 399668386549 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399668386583) 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, 392601050 + ... + 392602067.

It is an arithmetic number, because the mean of its divisors is an integer number (100113397545).

Almost surely, 2^399668386553 is an apocalyptic number.

It is an amenable number.

399668386553 is a deficient number, since it is larger than the sum of its proper divisors (785203627).

399668386553 is an equidigital number, since it uses as much as digits as its factorization.

399668386553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 785203626.

The product of its digits is 755827200, while the sum is 71.

The spelling of 399668386553 in words is "three hundred ninety-nine billion, six hundred sixty-eight million, three hundred eighty-six thousand, five hundred fifty-three".