19988720 has 20 divisors (see below), whose sum is σ = 46473960. Its totient is φ = 7995456.

The previous prime is 19988699. The next prime is 19988737. The reversal of 19988720 is 2788991.

It is a tau number, because it is divible by the number of its divisors (20).

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

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, 124850 + ... + 125009.

It is an arithmetic number, because the mean of its divisors is an integer number (2323698).

Almost surely, 2^19988720 is an apocalyptic number.

19988720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19988720 is an abundant number, since it is smaller than the sum of its proper divisors (26485240).

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

19988720 is a wasteful number, since it uses less digits than its factorization.

19988720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 249872 (or 249866 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 19988720 is about 4470.8746347890. The cubic root of 19988720 is about 271.3907210115.

The spelling of 19988720 in words is "nineteen million, nine hundred eighty-eight thousand, seven hundred twenty".