81584377875 has 1024 divisors, whose sum is σ = 225430732800. Its totient is φ = 27993600000.

The previous prime is 81584377871. The next prime is 81584377877. The reversal of 81584377875 is 57877348518.

81584377875 is a `hidden beast` number, since 81 + 58 + 437 + 7 + 8 + 75 = 666.

It is not a de Polignac number, because 81584377875 - 2² = 81584377871 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is not an unprimeable number, because it can be changed into a prime (81584377871) by changing a digit.

It is a polite number, since it can be written in 1023 ways as a sum of consecutive naturals, for example, 1989862855 + ... + 1989862895.

It is an arithmetic number, because the mean of its divisors is an integer number (220147200).

Almost surely, 2^81584377875 is an apocalyptic number.

81584377875 is an abundant number, since it is smaller than the sum of its proper divisors (143846354925).

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

81584377875 is a wasteful number, since it uses less digits than its factorization.

81584377875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 146 (or 130 counting only the distinct ones).

The product of its digits is 52684800, while the sum is 63.

The spelling of 81584377875 in words is "eighty-one billion, five hundred eighty-four million, three hundred seventy-seven thousand, eight hundred seventy-five".