19718920 has 48 divisors (see below), whose sum is σ = 48059460. Its totient is φ = 7278336.

The previous prime is 19718911. The next prime is 19718947. The reversal of 19718920 is 2981791.

It can be written as a sum of positive squares in 6 ways, for example, as 8145316 + 11573604 = 2854^2 + 3402^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 19718920.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5302 + ... + 8218.

Almost surely, 2^19718920 is an apocalyptic number.

19718920 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 19718920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24029730).

19718920 is an abundant number, since it is smaller than the sum of its proper divisors (28340540).

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

19718920 is a wasteful number, since it uses less digits than its factorization.

19718920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2954 (or 2937 counting only the distinct ones).

The product of its (nonzero) digits is 9072, while the sum is 37.

The square root of 19718920 is about 4440.5990586857. The cubic root of 19718920 is about 270.1641434462.

The spelling of 19718920 in words is "nineteen million, seven hundred eighteen thousand, nine hundred twenty".