81589644500 has 96 divisors (see below), whose sum is σ = 219313086720. Its totient is φ = 25821763200.

The previous prime is 81589644491. The next prime is 81589644557. The reversal of 81589644500 is 544698518.

It is a Harshad number since it is a multiple of its sum of digits (50).

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, 851090 + ... + 942089.

It is an arithmetic number, because the mean of its divisors is an integer number (2284511320).

Almost surely, 2^81589644500 is an apocalyptic number.

It is an amenable number.

81589644500 is an abundant number, since it is smaller than the sum of its proper divisors (137723442220).

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

81589644500 is a wasteful number, since it uses less digits than its factorization.

81589644500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1793218 (or 1793206 counting only the distinct ones).

The product of its (nonzero) digits is 1382400, while the sum is 50.

The spelling of 81589644500 in words is "eighty-one billion, five hundred eighty-nine million, six hundred forty-four thousand, five hundred".