16404002665 has 4 divisors (see below), whose sum is σ = 19684803204. Its totient is φ = 13123202128.

The previous prime is 16404002603. The next prime is 16404002723. The reversal of 16404002665 is 56620040461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56620040461 = 43 ⋅1316745127.

It can be written as a sum of positive squares in 2 ways, for example, as 8737949529 + 7666053136 = 93477^2 + 87556^2 .

It is a cyclic number.

It is not a de Polignac number, because 16404002665 - 2¹¹ = 16404000617 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 16404002665.

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, 1640400262 + ... + 1640400271.

It is an arithmetic number, because the mean of its divisors is an integer number (4921200801).

Almost surely, 2^16404002665 is an apocalyptic number.

It is an amenable number.

16404002665 is a deficient number, since it is larger than the sum of its proper divisors (3280800539).

16404002665 is an equidigital number, since it uses as much as digits as its factorization.

16404002665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3280800538.

The product of its (nonzero) digits is 34560, while the sum is 34.

The spelling of 16404002665 in words is "sixteen billion, four hundred four million, two thousand, six hundred sixty-five".