16978394 has 4 divisors (see below), whose sum is σ = 25467594. Its totient is φ = 8489196.

The previous prime is 16978373. The next prime is 16978399. The reversal of 16978394 is 49387961.

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

It can be written as a sum of positive squares in only one way, i.e., 16104169 + 874225 = 4013^2 + 935^2 .

It is not an unprimeable number, because it can be changed into a prime (16978399) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4244597 + ... + 4244600.

Almost surely, 2^16978394 is an apocalyptic number.

16978394 is a deficient number, since it is larger than the sum of its proper divisors (8489200).

16978394 is an equidigital number, since it uses as much as digits as its factorization.

16978394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8489199.

The product of its digits is 326592, while the sum is 47.

The square root of 16978394 is about 4120.4846802288. The cubic root of 16978394 is about 257.0191812963.

The spelling of 16978394 in words is "sixteen million, nine hundred seventy-eight thousand, three hundred ninety-four".