16664351623 has 4 divisors (see below), whose sum is σ = 17051894728. Its totient is φ = 16276808520.

The previous prime is 16664351593. The next prime is 16664351647. The reversal of 16664351623 is 32615346661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32615346661 = 1789 ⋅18231049.

It is a cyclic number.

It is not a de Polignac number, because 16664351623 - 2⁵ = 16664351591 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43), and also a Moran number because the ratio is a prime number: 387543061 = 16664351623 / (1 + 6 + 6 + 6 + 4 + 3 + 5 + 1 + 6 + 2 + 3).

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 16664351623.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16664351423) 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, 193771488 + ... + 193771573.

It is an arithmetic number, because the mean of its divisors is an integer number (4262973682).

Almost surely, 2^16664351623 is an apocalyptic number.

16664351623 is a deficient number, since it is larger than the sum of its proper divisors (387543105).

16664351623 is an equidigital number, since it uses as much as digits as its factorization.

16664351623 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 387543104.

The product of its digits is 466560, while the sum is 43.

The spelling of 16664351623 in words is "sixteen billion, six hundred sixty-four million, three hundred fifty-one thousand, six hundred twenty-three".