19921920 has 88 divisors (see below), whose sum is σ = 63768144. Its totient is φ = 5308416.

The previous prime is 19921901. The next prime is 19921921. The reversal of 19921920 is 2912991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19921921) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14712 + ... + 16008.

It is an arithmetic number, because the mean of its divisors is an integer number (724638).

Almost surely, 2^19921920 is an apocalyptic number.

19921920 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 19921920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31884072).

19921920 is an abundant number, since it is smaller than the sum of its proper divisors (43846224).

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

19921920 is a wasteful number, since it uses less digits than its factorization.

19921920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1325 (or 1307 counting only the distinct ones).

The product of its (nonzero) digits is 2916, while the sum is 33.

The square root of 19921920 is about 4463.3978088447. The cubic root of 19921920 is about 271.0880647693.

The spelling of 19921920 in words is "nineteen million, nine hundred twenty-one thousand, nine hundred twenty".