16597432921 has 4 divisors (see below), whose sum is σ = 16641226000. Its totient is φ = 16553639844.

The previous prime is 16597432913. The next prime is 16597432927. The reversal of 16597432921 is 12923479561.

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.

It is a cyclic number.

It is not a de Polignac number, because 16597432921 - 2³ = 16597432913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16597432927) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21895971 + ... + 21896728.

It is an arithmetic number, because the mean of its divisors is an integer number (4160306500).

Almost surely, 2^16597432921 is an apocalyptic number.

It is an amenable number.

16597432921 is a deficient number, since it is larger than the sum of its proper divisors (43793079).

16597432921 is an equidigital number, since it uses as much as digits as its factorization.

16597432921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43793078.

The product of its digits is 816480, while the sum is 49.

The spelling of 16597432921 in words is "sixteen billion, five hundred ninety-seven million, four hundred thirty-two thousand, nine hundred twenty-one".