71557 has 4 divisors (see below), whose sum is σ = 72160. Its totient is φ = 70956.

The previous prime is 71551. The next prime is 71563. The reversal of 71557 is 75517.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (71551) and next prime (71563).

It is a cyclic number.

It is not a de Polignac number, because 71557 - 2³ = 71549 is a prime.

It is the 268-th Hogben number.

It is a Duffinian number.

71557 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71551) by changing a digit.

It is a nontrivial repunit in base 267.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57 + ... + 382.

It is an arithmetic number, because the mean of its divisors is an integer number (18040).

2⁷¹⁵⁵⁷ is an apocalyptic number.

It is an amenable number.

71557 is a deficient number, since it is larger than the sum of its proper divisors (603).

71557 is a wasteful number, since it uses less digits than its factorization.

71557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 602.

The product of its digits is 1225, while the sum is 25.

The square root of 71557 is about 267.5014018655. The cubic root of 71557 is about 41.5161789146.

It can be divided in two parts, 715 and 57, that multiplied together give a triangular number (40755 = T₂₈₅).

The spelling of 71557 in words is "seventy-one thousand, five hundred fifty-seven".