81588490056 has 128 divisors (see below), whose sum is σ = 234086400000. Its totient is φ = 26303019840.

The previous prime is 81588490043. The next prime is 81588490057. The reversal of 81588490056 is 65009488518.

It is a happy number.

81588490056 is a `hidden beast` number, since 8 + 1 + 588 + 4 + 9 + 0 + 0 + 56 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a junction number, because it is equal to n+sod(n) for n = 81588489984 and 81588490011.

It is not an unprimeable number, because it can be changed into a prime (81588490057) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16998745 + ... + 17003543.

It is an arithmetic number, because the mean of its divisors is an integer number (1828800000).

Almost surely, 2^81588490056 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 81588490056, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (117043200000).

81588490056 is an abundant number, since it is smaller than the sum of its proper divisors (152497909944).

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

81588490056 is a wasteful number, since it uses less digits than its factorization.

81588490056 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7384 (or 7374 counting only the distinct ones).

The product of its (nonzero) digits is 2764800, while the sum is 54.

The spelling of 81588490056 in words is "eighty-one billion, five hundred eighty-eight million, four hundred ninety thousand, fifty-six".