7981820 has 96 divisors (see below), whose sum is σ = 21482496. Its totient is φ = 2419200.

The previous prime is 7981819. The next prime is 7981837. The reversal of 7981820 is 281897.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (35).

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, 109304 + ... + 109376.

It is an arithmetic number, because the mean of its divisors is an integer number (223776).

Almost surely, 2^7981820 is an apocalyptic number.

7981820 is a gapful number since it is divisible by the number (70) 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 7981820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10741248).

7981820 is an abundant number, since it is smaller than the sum of its proper divisors (13500676).

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

7981820 is a wasteful number, since it uses less digits than its factorization.

7981820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171 (or 169 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 35.

The square root of 7981820 is about 2825.2114965078. The cubic root of 7981820 is about 199.8483850936.

The spelling of 7981820 in words is "seven million, nine hundred eighty-one thousand, eight hundred twenty".