16978505 has 4 divisors (see below), whose sum is σ = 20374212. Its totient is φ = 13582800.

The previous prime is 16978487. The next prime is 16978513. The reversal of 16978505 is 50587961.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10316944 + 6661561 = 3212^2 + 2581^2 .

It is not a de Polignac number, because 16978505 - 2²⁰ = 15929929 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1697846 + ... + 1697855.

It is an arithmetic number, because the mean of its divisors is an integer number (5093553).

Almost surely, 2^16978505 is an apocalyptic number.

It is an amenable number.

16978505 is a deficient number, since it is larger than the sum of its proper divisors (3395707).

16978505 is an equidigital number, since it uses as much as digits as its factorization.

16978505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3395706.

The product of its (nonzero) digits is 75600, while the sum is 41.

The square root of 16978505 is about 4120.4981494960. The cubic root of 16978505 is about 257.0197414017.

The spelling of 16978505 in words is "sixteen million, nine hundred seventy-eight thousand, five hundred five".