82557981 has 32 divisors (see below), whose sum is σ = 134467200. Its totient is φ = 49645440.

The previous prime is 82557973. The next prime is 82557997. The reversal of 82557981 is 18975528.

It is a happy number.

82557981 is a `hidden beast` number, since 8 + 2 + 557 + 98 + 1 = 666.

It is not a de Polignac number, because 82557981 - 2³ = 82557973 is a prime.

It is a super-2 number, since 2×82557981² = 13631640453592722, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (82557931) 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, 39675 + ... + 41703.

It is an arithmetic number, because the mean of its divisors is an integer number (4202100).

Almost surely, 2^82557981 is an apocalyptic number.

It is an amenable number.

82557981 is a deficient number, since it is larger than the sum of its proper divisors (51909219).

82557981 is a wasteful number, since it uses less digits than its factorization.

82557981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2186 (or 2180 counting only the distinct ones).

The product of its digits is 201600, while the sum is 45.

The square root of 82557981 is about 9086.1422507024. The cubic root of 82557981 is about 435.4313438406.

It can be divided in two parts, 82557 and 981, that added together give a palindrome (83538).

The spelling of 82557981 in words is "eighty-two million, five hundred fifty-seven thousand, nine hundred eighty-one".