81289588 has 24 divisors (see below), whose sum is σ = 145156032. Its totient is φ = 39824064.

The previous prime is 81289577. The next prime is 81289591. The reversal of 81289588 is 88598218.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 47931 + ... + 49597.

It is an arithmetic number, because the mean of its divisors is an integer number (6048168).

Almost surely, 2^81289588 is an apocalyptic number.

It is an amenable number.

81289588 is a deficient number, since it is larger than the sum of its proper divisors (63866444).

81289588 is a wasteful number, since it uses less digits than its factorization.

81289588 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1911 (or 1909 counting only the distinct ones).

The product of its digits is 368640, while the sum is 49.

The square root of 81289588 is about 9016.0738683753. The cubic root of 81289588 is about 433.1898851949.

The spelling of 81289588 in words is "eighty-one million, two hundred eighty-nine thousand, five hundred eighty-eight".