16989978 has 8 divisors (see below), whose sum is σ = 33979968. Its totient is φ = 5663324.

The previous prime is 16989967. The next prime is 16989991. The reversal of 16989978 is 87998961.

It is a sphenic number, since it is the product of 3 distinct primes.

16989978 is an admirable 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, 1415826 + ... + 1415837.

It is an arithmetic number, because the mean of its divisors is an integer number (4247496).

Almost surely, 2^16989978 is an apocalyptic number.

16989978 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

16989978 is a wasteful number, since it uses less digits than its factorization.

16989978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2831668.

The product of its digits is 1959552, while the sum is 57.

The square root of 16989978 is about 4121.8901004272. The cubic root of 16989978 is about 257.0776209292.

The spelling of 16989978 in words is "sixteen million, nine hundred eighty-nine thousand, nine hundred seventy-eight".