1921553920 has 320 divisors, whose sum is σ = 5630264640. Its totient is φ = 619315200.

The previous prime is 1921553899. The next prime is 1921553927. The reversal of 1921553920 is 293551291.

It is a tau number, because it is divible by the number of its divisors (320).

It is a self number, because there is not a number n which added to its sum of digits gives 1921553920.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1921553927) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10616230 + ... + 10616410.

It is an arithmetic number, because the mean of its divisors is an integer number (17594577).

Almost surely, 2^1921553920 is an apocalyptic number.

1921553920 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 1921553920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2815132320).

1921553920 is an abundant number, since it is smaller than the sum of its proper divisors (3708710720).

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

1921553920 is a wasteful number, since it uses less digits than its factorization.

1921553920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257 (or 241 counting only the distinct ones).

The product of its (nonzero) digits is 24300, while the sum is 37.

The square root of 1921553920 is about 43835.5326190979. The cubic root of 1921553920 is about 1243.2282168766.

The spelling of 1921553920 in words is "one billion, nine hundred twenty-one million, five hundred fifty-three thousand, nine hundred twenty".