16434618721 has 4 divisors (see below), whose sum is σ = 16964767744. Its totient is φ = 15904469700.

The previous prime is 16434618677. The next prime is 16434618749. The reversal of 16434618721 is 12781643461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12781643461 = 1409 ⋅9071429.

It is a cyclic number.

It is not a de Polignac number, because 16434618721 - 2⁷ = 16434618593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16434618121) 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, 265074465 + ... + 265074526.

It is an arithmetic number, because the mean of its divisors is an integer number (4241191936).

Almost surely, 2^16434618721 is an apocalyptic number.

It is an amenable number.

16434618721 is a deficient number, since it is larger than the sum of its proper divisors (530149023).

16434618721 is an equidigital number, since it uses as much as digits as its factorization.

16434618721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530149022.

The product of its digits is 193536, while the sum is 43.

The spelling of 16434618721 in words is "sixteen billion, four hundred thirty-four million, six hundred eighteen thousand, seven hundred twenty-one".