81357 has 8 divisors (see below), whose sum is σ = 110976. Its totient is φ = 52992.

The previous prime is 81353. The next prime is 81359. The reversal of 81357 is 75318.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81357 - 2² = 81353 is a prime.

It is a super-2 number, since 2×81357² = 13237922898, which contains 22 as substring.

81357 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 148 + ... + 429.

It is an arithmetic number, because the mean of its divisors is an integer number (13872).

2⁸¹³⁵⁷ is an apocalyptic number.

It is an amenable number.

81357 is a deficient number, since it is larger than the sum of its proper divisors (29619).

81357 is a wasteful number, since it uses less digits than its factorization.

81357 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 627.

The product of its digits is 840, while the sum is 24.

The square root of 81357 is about 285.2314849381. The cubic root of 81357 is about 43.3309597648.

The spelling of 81357 in words is "eighty-one thousand, three hundred fifty-seven".