16991855 has 8 divisors (see below), whose sum is σ = 20724864. Its totient is φ = 13370400.

The previous prime is 16991851. The next prime is 16991861. The reversal of 16991855 is 55819961.

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

It is not a de Polignac number, because 16991855 - 2² = 16991851 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 (16991851) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27551 + ... + 28160.

It is an arithmetic number, because the mean of its divisors is an integer number (2590608).

Almost surely, 2^16991855 is an apocalyptic number.

16991855 is a deficient number, since it is larger than the sum of its proper divisors (3733009).

16991855 is an equidigital number, since it uses as much as digits as its factorization.

16991855 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55777.

The product of its digits is 97200, while the sum is 44.

The square root of 16991855 is about 4122.1177809471. The cubic root of 16991855 is about 257.0870876263.

The spelling of 16991855 in words is "sixteen million, nine hundred ninety-one thousand, eight hundred fifty-five".