921680 has 40 divisors (see below), whose sum is σ = 2202984. Its totient is φ = 358400.

The previous prime is 921677. The next prime is 921703. The reversal of 921680 is 86129.

It can be written as a sum of positive squares in 4 ways, for example, as 15376 + 906304 = 124^2 + 952^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 921680.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3140 + ... + 3420.

2⁹²¹⁶⁸⁰ 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 921680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1101492).

921680 is an abundant number, since it is smaller than the sum of its proper divisors (1281304).

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

921680 is a wasteful number, since it uses less digits than its factorization.

921680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335 (or 329 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 921680 is about 960.0416657625. The cubic root of 921680 is about 97.3180476820.

The spelling of 921680 in words is "nine hundred twenty-one thousand, six hundred eighty".