16665026639 has 4 divisors (see below), whose sum is σ = 17239682760. Its totient is φ = 16090370520.

The previous prime is 16665026621. The next prime is 16665026641. The reversal of 16665026639 is 93662056661.

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

It is a cyclic number.

It is not a de Polignac number, because 16665026639 - 2⁸ = 16665026383 is a prime.

It is a super-2 number, since 2×16665026639² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16665026669) 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, 287328017 + ... + 287328074.

It is an arithmetic number, because the mean of its divisors is an integer number (4309920690).

Almost surely, 2^16665026639 is an apocalyptic number.

16665026639 is a deficient number, since it is larger than the sum of its proper divisors (574656121).

16665026639 is an equidigital number, since it uses as much as digits as its factorization.

16665026639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 574656120.

The product of its (nonzero) digits is 2099520, while the sum is 50.

The spelling of 16665026639 in words is "sixteen billion, six hundred sixty-five million, twenty-six thousand, six hundred thirty-nine".