82705581 has 36 divisors (see below), whose sum is σ = 139924512. Its totient is φ = 46935504.

The previous prime is 82705547. The next prime is 82705583. The reversal of 82705581 is 18550728.

82705581 is a `hidden beast` number, since 8 + 2 + 70 + 5 + 581 = 666.

It is not a de Polignac number, because 82705581 - 2¹³ = 82697389 is a prime.

It is a super-2 number, since 2×82705581² = 13680426257095122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82705583) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 73086 + ... + 74208.

It is an arithmetic number, because the mean of its divisors is an integer number (3886792).

Almost surely, 2^82705581 is an apocalyptic number.

It is an amenable number.

82705581 is a deficient number, since it is larger than the sum of its proper divisors (57218931).

82705581 is a wasteful number, since it uses less digits than its factorization.

82705581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1310 (or 1300 counting only the distinct ones).

The product of its (nonzero) digits is 22400, while the sum is 36.

The square root of 82705581 is about 9094.2608825566. The cubic root of 82705581 is about 435.6906823983.

The spelling of 82705581 in words is "eighty-two million, seven hundred five thousand, five hundred eighty-one".