16809978 has 16 divisors (see below), whose sum is σ = 33731136. Its totient is φ = 5584800.

The previous prime is 16809977. The next prime is 16809979. The reversal of 16809978 is 87990861.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (16809977) and next prime (16809979).

It is not an unprimeable number, because it can be changed into a prime (16809971) 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, 2598 + ... + 6353.

It is an arithmetic number, because the mean of its divisors is an integer number (2108196).

Almost surely, 2^16809978 is an apocalyptic number.

16809978 is an abundant number, since it is smaller than the sum of its proper divisors (16921158).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16809978 is a wasteful number, since it uses less digits than its factorization.

16809978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9269.

The product of its (nonzero) digits is 217728, while the sum is 48.

The square root of 16809978 is about 4099.9973170723. The cubic root of 16809978 is about 256.1665277994.

The spelling of 16809978 in words is "sixteen million, eight hundred nine thousand, nine hundred seventy-eight".