19778868 has 72 divisors (see below), whose sum is σ = 53114880. Its totient is φ = 6194880.

The previous prime is 19778861. The next prime is 19778881. The reversal of 19778868 is 86887791.

It is a super-2 number, since 2×19778868² = 782407238722848, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19778861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 41053 + ... + 41531.

Almost surely, 2^19778868 is an apocalyptic number.

19778868 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19778868, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26557440).

19778868 is an abundant number, since it is smaller than the sum of its proper divisors (33336012).

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

19778868 is a wasteful number, since it uses less digits than its factorization.

19778868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 557 (or 552 counting only the distinct ones).

The product of its digits is 1354752, while the sum is 54.

The square root of 19778868 is about 4447.3439264352. The cubic root of 19778868 is about 270.4376441469.

The spelling of 19778868 in words is "nineteen million, seven hundred seventy-eight thousand, eight hundred sixty-eight".