16978091 has 4 divisors (see below), whose sum is σ = 18284112. Its totient is φ = 15672072.

The previous prime is 16978061. The next prime is 16978097. The reversal of 16978091 is 19087961.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19087961 = 857 ⋅22273.

It is a de Polignac number, because none of the positive numbers 2^k-16978091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (16978097) 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, 652991 + ... + 653016.

It is an arithmetic number, because the mean of its divisors is an integer number (4571028).

Almost surely, 2^16978091 is an apocalyptic number.

16978091 is a deficient number, since it is larger than the sum of its proper divisors (1306021).

16978091 is a wasteful number, since it uses less digits than its factorization.

16978091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1306020.

The product of its (nonzero) digits is 27216, while the sum is 41.

The square root of 16978091 is about 4120.4479125454. The cubic root of 16978091 is about 257.0176523477.

The spelling of 16978091 in words is "sixteen million, nine hundred seventy-eight thousand, ninety-one".