399617777665 has 8 divisors (see below), whose sum is σ = 491237463528. Its totient is φ = 311896801920.

The previous prime is 399617777641. The next prime is 399617777677. The reversal of 399617777665 is 566777716993.

It can be written as a sum of positive squares in 4 ways, for example, as 21505929201 + 378111848464 = 146649^2 + 614908^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 399617777665 - 2⁵ = 399617777633 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 974677302 + ... + 974677711.

It is an arithmetic number, because the mean of its divisors is an integer number (61404682941).

Almost surely, 2^399617777665 is an apocalyptic number.

It is an amenable number.

399617777665 is a deficient number, since it is larger than the sum of its proper divisors (91619685863).

399617777665 is a wasteful number, since it uses less digits than its factorization.

399617777665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1949355059.

The product of its digits is 630118440, while the sum is 73.

The spelling of 399617777665 in words is "three hundred ninety-nine billion, six hundred seventeen million, seven hundred seventy-seven thousand, six hundred sixty-five".