7856820 has 36 divisors (see below), whose sum is σ = 23832900. Its totient is φ = 2095104.

The previous prime is 7856819. The next prime is 7856843. The reversal of 7856820 is 286587.

7856820 is a `hidden beast` number, since 78 + 568 + 20 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 3370896 + 4485924 = 1836^2 + 2118^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21645 + ... + 22004.

It is an arithmetic number, because the mean of its divisors is an integer number (662025).

Almost surely, 2^7856820 is an apocalyptic number.

It is an amenable number.

7856820 is an abundant number, since it is smaller than the sum of its proper divisors (15976080).

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

7856820 is a wasteful number, since it uses less digits than its factorization.

7856820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43664 (or 43659 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 7856820 is about 2803.0019621827. The cubic root of 7856820 is about 198.7996434671.

The spelling of 7856820 in words is "seven million, eight hundred fifty-six thousand, eight hundred twenty".