16390978 has 4 divisors (see below), whose sum is σ = 24586470. Its totient is φ = 8195488.

The previous prime is 16390961. The next prime is 16390993. The reversal of 16390978 is 87909361.

16390978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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., 16378209 + 12769 = 4047^2 + 113^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4097743 + ... + 4097746.

Almost surely, 2^16390978 is an apocalyptic number.

16390978 is a deficient number, since it is larger than the sum of its proper divisors (8195492).

16390978 is an equidigital number, since it uses as much as digits as its factorization.

16390978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8195491.

The product of its (nonzero) digits is 81648, while the sum is 43.

The square root of 16390978 is about 4048.5772809717. The cubic root of 16390978 is about 254.0202207640.

The spelling of 16390978 in words is "sixteen million, three hundred ninety thousand, nine hundred seventy-eight".