19819920 has 80 divisors (see below), whose sum is σ = 61871040. Its totient is φ = 5248512.

The previous prime is 19819903. The next prime is 19819979. The reversal of 19819920 is 2991891.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64407 + ... + 64713.

It is an arithmetic number, because the mean of its divisors is an integer number (773388).

Almost surely, 2^19819920 is an apocalyptic number.

19819920 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 19819920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30935520).

19819920 is an abundant number, since it is smaller than the sum of its proper divisors (42051120).

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

19819920 is a wasteful number, since it uses less digits than its factorization.

19819920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592 (or 586 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 39.

The square root of 19819920 is about 4451.9568731065. The cubic root of 19819920 is about 270.6246169992.

The spelling of 19819920 in words is "nineteen million, eight hundred nineteen thousand, nine hundred twenty".