921817680 has 160 divisors (see below), whose sum is σ = 3437875200. Its totient is φ = 199604736.

The previous prime is 921817651. The next prime is 921817763. The reversal of 921817680 is 86718129.

921817680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 17481 + ... + 46359.

It is an arithmetic number, because the mean of its divisors is an integer number (21486720).

Almost surely, 2^921817680 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 921817680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1718937600).

921817680 is an abundant number, since it is smaller than the sum of its proper divisors (2516057520).

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

921817680 is a wasteful number, since it uses less digits than its factorization.

921817680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28921 (or 28915 counting only the distinct ones).

The product of its (nonzero) digits is 48384, while the sum is 42.

The square root of 921817680 is about 30361.4505582326. The cubic root of 921817680 is about 973.2289321103.

The spelling of 921817680 in words is "nine hundred twenty-one million, eight hundred seventeen thousand, six hundred eighty".