19978868 has 36 divisors (see below), whose sum is σ = 43805412. Its totient is φ = 7902720.

The previous prime is 19978867. The next prime is 19978873. The reversal of 19978868 is 86887991.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4831204 + 15147664 = 2198^2 + 3892^2 .

It is a super-2 number, since 2×19978868² = 798310333122848, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19978867) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1373 + ... + 6468.

It is an arithmetic number, because the mean of its divisors is an integer number (1216817).

Almost surely, 2^19978868 is an apocalyptic number.

It is an amenable number.

19978868 is an abundant number, since it is smaller than the sum of its proper divisors (23826544).

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

19978868 is a wasteful number, since it uses less digits than its factorization.

19978868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7872 (or 7863 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 56.

The square root of 19978868 is about 4469.7727011561. The cubic root of 19978868 is about 271.3461261803.

The spelling of 19978868 in words is "nineteen million, nine hundred seventy-eight thousand, eight hundred sixty-eight".