19978984 has 16 divisors (see below), whose sum is σ = 37736100. Its totient is φ = 9916032.

The previous prime is 19978979. The next prime is 19978991. The reversal of 19978984 is 48987991.

It can be written as a sum of positive squares in 2 ways, for example, as 16630084 + 3348900 = 4078^2 + 1830^2 .

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, 8019 + ... + 10210.

Almost surely, 2^19978984 is an apocalyptic number.

It is an amenable number.

19978984 is a deficient number, since it is larger than the sum of its proper divisors (17757116).

19978984 is a wasteful number, since it uses less digits than its factorization.

19978984 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18372 (or 18368 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 55.

The square root of 19978984 is about 4469.7856771886. The cubic root of 19978984 is about 271.3466513367.

The spelling of 19978984 in words is "nineteen million, nine hundred seventy-eight thousand, nine hundred eighty-four".