19776720 has 80 divisors (see below), whose sum is σ = 64549440. Its totient is φ = 4995072.

The previous prime is 19776697. The next prime is 19776737. The reversal of 19776720 is 2767791.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×19776720² = 782237307916800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2392 + ... + 6728.

It is an arithmetic number, because the mean of its divisors is an integer number (806868).

Almost surely, 2^19776720 is an apocalyptic number.

19776720 is a gapful number since it is divisible by the number (10) 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 19776720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32274720).

19776720 is an abundant number, since it is smaller than the sum of its proper divisors (44772720).

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

19776720 is a wasteful number, since it uses less digits than its factorization.

19776720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4372 (or 4366 counting only the distinct ones).

The product of its (nonzero) digits is 37044, while the sum is 39.

The square root of 19776720 is about 4447.1024274240. The cubic root of 19776720 is about 270.4278538817.

The spelling of 19776720 in words is "nineteen million, seven hundred seventy-six thousand, seven hundred twenty".