1399165645 has 4 divisors (see below), whose sum is σ = 1678998780. Its totient is φ = 1119332512.

The previous prime is 1399165613. The next prime is 1399165667. The reversal of 1399165645 is 5465619931.

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 1005460681 + 393704964 = 31709^2 + 19842^2 .

It is a cyclic number.

It is not a de Polignac number, because 1399165645 - 2⁵ = 1399165613 is a prime.

It is a super-3 number, since 3×1399165645³ (a number of 28 digits) contains 333 as substring.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 139916560 + ... + 139916569.

It is an arithmetic number, because the mean of its divisors is an integer number (419749695).

Almost surely, 2^1399165645 is an apocalyptic number.

It is an amenable number.

1399165645 is a deficient number, since it is larger than the sum of its proper divisors (279833135).

1399165645 is an equidigital number, since it uses as much as digits as its factorization.

1399165645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 279833134.

The product of its digits is 874800, while the sum is 49.

The square root of 1399165645 is about 37405.4226683779. The cubic root of 1399165645 is about 1118.4666637014.

The spelling of 1399165645 in words is "one billion, three hundred ninety-nine million, one hundred sixty-five thousand, six hundred forty-five".