16791991 has 8 divisors (see below), whose sum is σ = 17715200. Its totient is φ = 15872760.

The previous prime is 16791967. The next prime is 16792021. The reversal of 16791991 is 19919761.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 16791991 - 2⁵ = 16791959 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16791911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12490 + ... + 13768.

It is an arithmetic number, because the mean of its divisors is an integer number (2214400).

Almost surely, 2^16791991 is an apocalyptic number.

16791991 is a deficient number, since it is larger than the sum of its proper divisors (923209).

16791991 is a wasteful number, since it uses less digits than its factorization.

16791991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1989.

The product of its digits is 30618, while the sum is 43.

The square root of 16791991 is about 4097.8031919554. The cubic root of 16791991 is about 256.0751274866.

The spelling of 16791991 in words is "sixteen million, seven hundred ninety-one thousand, nine hundred ninety-one".