81243490500 has 288 divisors, whose sum is σ = 266594520192. Its totient is φ = 20811168000.

The previous prime is 81243490487. The next prime is 81243490507. The reversal of 81243490500 is 509434218.

81243490500 is a `hidden beast` number, since 81 + 2 + 43 + 490 + 50 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (81243490507) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 11800059 + ... + 11806941.

Almost surely, 2^81243490500 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81243490500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133297260096).

81243490500 is an abundant number, since it is smaller than the sum of its proper divisors (185351029692).

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

81243490500 is a wasteful number, since it uses less digits than its factorization.

81243490500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7012 (or 6997 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The spelling of 81243490500 in words is "eighty-one billion, two hundred forty-three million, four hundred ninety thousand, five hundred".