7881644 has 12 divisors (see below), whose sum is σ = 13812624. Its totient is φ = 3935184.

The previous prime is 7881619. The next prime is 7881647. The reversal of 7881644 is 4461887.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 7881598 and 7881607.

It is not an unprimeable number, because it can be changed into a prime (7881647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4337 + ... + 5879.

It is an arithmetic number, because the mean of its divisors is an integer number (1151052).

Almost surely, 2^7881644 is an apocalyptic number.

It is an amenable number.

7881644 is a deficient number, since it is larger than the sum of its proper divisors (5930980).

7881644 is a wasteful number, since it uses less digits than its factorization.

7881644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2824 (or 2822 counting only the distinct ones).

The product of its digits is 43008, while the sum is 38.

The square root of 7881644 is about 2807.4265796277. The cubic root of 7881644 is about 199.0087956854.

The spelling of 7881644 in words is "seven million, eight hundred eighty-one thousand, six hundred forty-four".