82581585381 has 24 divisors (see below), whose sum is σ = 119985727680. Its totient is φ = 54730933056.

The previous prime is 82581585377. The next prime is 82581585397. The reversal of 82581585381 is 18358518528.

82581585381 is a `hidden beast` number, since 8 + 2 + 58 + 1 + 58 + 538 + 1 = 666.

It is not a de Polignac number, because 82581585381 - 2² = 82581585377 is a prime.

It is a super-3 number, since 3×82581585381³ (a number of 34 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82581585481) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8722056 + ... + 8731518.

It is an arithmetic number, because the mean of its divisors is an integer number (4999405320).

Almost surely, 2^82581585381 is an apocalyptic number.

It is an amenable number.

82581585381 is a deficient number, since it is larger than the sum of its proper divisors (37404142299).

82581585381 is a wasteful number, since it uses less digits than its factorization.

82581585381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15065 (or 15062 counting only the distinct ones).

The product of its digits is 3072000, while the sum is 54.

The spelling of 82581585381 in words is "eighty-two billion, five hundred eighty-one million, five hundred eighty-five thousand, three hundred eighty-one".