7681644 has 72 divisors (see below), whose sum is σ = 20471360. Its totient is φ = 2426112.

The previous prime is 7681631. The next prime is 7681651. The reversal of 7681644 is 4461867.

7681644 is a `hidden beast` number, since 7 + 6 + 8 + 1 + 644 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 7681599 and 7681608.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 97197 + ... + 97275.

Almost surely, 2^7681644 is an apocalyptic number.

7681644 is a gapful number since it is divisible by the number (74) 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 7681644, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10235680).

7681644 is an abundant number, since it is smaller than the sum of its proper divisors (12789716).

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

7681644 is a wasteful number, since it uses less digits than its factorization.

7681644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 199 (or 194 counting only the distinct ones).

The product of its digits is 32256, while the sum is 36.

The square root of 7681644 is about 2771.5778899392. The cubic root of 7681644 is about 197.3110429026.

The spelling of 7681644 in words is "seven million, six hundred eighty-one thousand, six hundred forty-four".