16981121 has 4 divisors (see below), whose sum is σ = 17045952. Its totient is φ = 16916292.

The previous prime is 16981109. The next prime is 16981127. The reversal of 16981121 is 12118961.

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 16981121 - 2⁶ = 16981057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16981127) 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, 32021 + ... + 32546.

It is an arithmetic number, because the mean of its divisors is an integer number (4261488).

Almost surely, 2^16981121 is an apocalyptic number.

It is an amenable number.

16981121 is a deficient number, since it is larger than the sum of its proper divisors (64831).

16981121 is an equidigital number, since it uses as much as digits as its factorization.

16981121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64830.

The product of its digits is 864, while the sum is 29.

The square root of 16981121 is about 4120.8155746163. The cubic root of 16981121 is about 257.0329410152.

The spelling of 16981121 in words is "sixteen million, nine hundred eighty-one thousand, one hundred twenty-one".