71440 has 40 divisors (see below), whose sum is σ = 178560. Its totient is φ = 26496.

The previous prime is 71437. The next prime is 71443. The reversal of 71440 is 4417.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (71437) and next prime (71443).

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (16).

It is not an unprimeable number, because it can be changed into a prime (71443) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1497 + ... + 1543.

It is an arithmetic number, because the mean of its divisors is an integer number (4464).

2⁷¹⁴⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89280).

71440 is an abundant number, since it is smaller than the sum of its proper divisors (107120).

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

71440 is a wasteful number, since it uses less digits than its factorization.

71440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79 (or 73 counting only the distinct ones).

The product of its (nonzero) digits is 112, while the sum is 16.

The square root of 71440 is about 267.2826219566. The cubic root of 71440 is about 41.4935394211.

71440 divided by its sum of digits (16) gives a triangular number (4465 = T₉₄).

Adding to 71440 its reverse (4417), we get a palindrome (75857).

The spelling of 71440 in words is "seventy-one thousand, four hundred forty", and thus it is an iban number.