19978416 has 30 divisors (see below), whose sum is σ = 55912220. Its totient is φ = 6659424.

The previous prime is 19978393. The next prime is 19978457. The reversal of 19978416 is 61487991.

It is a happy number.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 69226 + ... + 69513.

Almost surely, 2^19978416 is an apocalyptic number.

19978416 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

19978416 is an abundant number, since it is smaller than the sum of its proper divisors (35933804).

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

19978416 is a wasteful number, since it uses less digits than its factorization.

19978416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138753 (or 138744 counting only the distinct ones).

The product of its digits is 108864, while the sum is 45.

The square root of 19978416 is about 4469.7221390149. The cubic root of 19978416 is about 271.3440798619.

The spelling of 19978416 in words is "nineteen million, nine hundred seventy-eight thousand, four hundred sixteen".