81274557 has 32 divisors (see below), whose sum is σ = 133869568. Its totient is φ = 42710976.

The previous prime is 81274549. The next prime is 81274561. The reversal of 81274557 is 75547218.

It is not a de Polignac number, because 81274557 - 2³ = 81274549 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81274507) 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, 126078 + ... + 126720.

It is an arithmetic number, because the mean of its divisors is an integer number (4183424).

Almost surely, 2^81274557 is an apocalyptic number.

It is an amenable number.

81274557 is a deficient number, since it is larger than the sum of its proper divisors (52595011).

81274557 is a wasteful number, since it uses less digits than its factorization.

81274557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1129.

The product of its digits is 78400, while the sum is 39.

The square root of 81274557 is about 9015.2402630213. The cubic root of 81274557 is about 433.1631836263.

The spelling of 81274557 in words is "eighty-one million, two hundred seventy-four thousand, five hundred fifty-seven".