7821920 has 96 divisors (see below), whose sum is σ = 20321280. Its totient is φ = 2833920.

The previous prime is 7821917. The next prime is 7821937. The reversal of 7821920 is 291287.

It is a happy number.

It is a super-2 number, since 2×7821920² = 122364864972800, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 94199 + ... + 94281.

It is an arithmetic number, because the mean of its divisors is an integer number (211680).

Almost surely, 2^7821920 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 7821920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10160640).

7821920 is an abundant number, since it is smaller than the sum of its proper divisors (12499360).

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

7821920 is a wasteful number, since it uses less digits than its factorization.

7821920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148 (or 140 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 29.

The square root of 7821920 is about 2796.7695650518. The cubic root of 7821920 is about 198.5048504928.

The spelling of 7821920 in words is "seven million, eight hundred twenty-one thousand, nine hundred twenty".