71540 has 36 divisors (see below), whose sum is σ = 177156. Its totient is φ = 24192.

The previous prime is 71537. The next prime is 71549. The reversal of 71540 is 4517.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 33124 + 38416 = 182^2 + 196^2 .

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71549) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 944 + ... + 1016.

It is an arithmetic number, because the mean of its divisors is an integer number (4921).

2⁷¹⁵⁴⁰ is an apocalyptic number.

71540 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88578).

71540 is an abundant number, since it is smaller than the sum of its proper divisors (105616).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

71540 is a wasteful number, since it uses less digits than its factorization.

71540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 17.

The square root of 71540 is about 267.4696244436. The cubic root of 71540 is about 41.5128909486.

The spelling of 71540 in words is "seventy-one thousand, five hundred forty".