399193387765 has 4 divisors (see below), whose sum is σ = 479032065324. Its totient is φ = 319354710208.

The previous prime is 399193387763. The next prime is 399193387783. The reversal of 399193387765 is 567783391993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 567783391993 = 71 ⋅7996949183.

It can be written as a sum of positive squares in 2 ways, for example, as 253332029041 + 145861358724 = 503321^2 + 381918^2 .

It is a cyclic number.

It is not a de Polignac number, because 399193387765 - 2¹ = 399193387763 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 399193387694 and 399193387703.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399193387763) 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, 39919338772 + ... + 39919338781.

It is an arithmetic number, because the mean of its divisors is an integer number (119758016331).

Almost surely, 2^399193387765 is an apocalyptic number.

It is an amenable number.

399193387765 is a deficient number, since it is larger than the sum of its proper divisors (79838677559).

399193387765 is an equidigital number, since it uses as much as digits as its factorization.

399193387765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79838677558.

The product of its digits is 231472080, while the sum is 70.

The spelling of 399193387765 in words is "three hundred ninety-nine billion, one hundred ninety-three million, three hundred eighty-seven thousand, seven hundred sixty-five".