81959500 has 48 divisors (see below), whose sum is σ = 204579648. Its totient is φ = 28099200.

The previous prime is 81959491. The next prime is 81959503. The reversal of 81959500 is 595918.

It is a self number, because there is not a number n which added to its sum of digits gives 81959500.

It is not an unprimeable number, because it can be changed into a prime (81959503) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8209 + ... + 15208.

It is an arithmetic number, because the mean of its divisors is an integer number (4262076).

Almost surely, 2^81959500 is an apocalyptic number.

It is an amenable number.

81959500 is an abundant number, since it is smaller than the sum of its proper divisors (122620148).

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

81959500 is a wasteful number, since it uses less digits than its factorization.

81959500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23443 (or 23431 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 37.

The square root of 81959500 is about 9053.1486235453. The cubic root of 81959500 is about 434.3766117981.

The spelling of 81959500 in words is "eighty-one million, nine hundred fifty-nine thousand, five hundred".