1921985280 has 288 divisors, whose sum is σ = 7181798400. Its totient is φ = 485388288.

The previous prime is 1921985251. The next prime is 1921985291. The reversal of 1921985280 is 825891291.

1921985280 is a `hidden beast` number, since 19 + 21 + 98 + 528 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 655177 + ... + 658103.

It is an arithmetic number, because the mean of its divisors is an integer number (24936800).

Almost surely, 2^1921985280 is an apocalyptic number.

1921985280 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 1921985280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3590899200).

1921985280 is an abundant number, since it is smaller than the sum of its proper divisors (5259813120).

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

1921985280 is a wasteful number, since it uses less digits than its factorization.

1921985280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2976 (or 2956 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 45.

The square root of 1921985280 is about 43840.4525524087. The cubic root of 1921985280 is about 1243.3212386048.

The spelling of 1921985280 in words is "one billion, nine hundred twenty-one million, nine hundred eighty-five thousand, two hundred eighty".