81087644 has 12 divisors (see below), whose sum is σ = 154803768. Its totient is φ = 36858000.

The previous prime is 81087641. The next prime is 81087659. The reversal of 81087644 is 44678018.

It is a junction number, because it is equal to n+sod(n) for n = 81087598 and 81087607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81087641) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 921407 + ... + 921494.

It is an arithmetic number, because the mean of its divisors is an integer number (12900314).

Almost surely, 2^81087644 is an apocalyptic number.

It is an amenable number.

81087644 is a deficient number, since it is larger than the sum of its proper divisors (73716124).

81087644 is a wasteful number, since it uses less digits than its factorization.

81087644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1842916 (or 1842914 counting only the distinct ones).

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

The square root of 81087644 is about 9004.8677946986. The cubic root of 81087644 is about 432.8308698055.

The spelling of 81087644 in words is "eighty-one million, eighty-seven thousand, six hundred forty-four".