79540 has 24 divisors (see below), whose sum is σ = 172872. Its totient is φ = 30720.

The previous prime is 79537. The next prime is 79549. The reversal of 79540 is 4597.

79540 = T₄₂ + T₄₃ + ... + T₈₁.

It can be written as a sum of positive squares in 4 ways, for example, as 16 + 79524 = 4^2 + 282^2 .

It is a super-2 number, since 2×79540² = 12653223200, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79549) 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, 772 + ... + 868.

It is an arithmetic number, because the mean of its divisors is an integer number (7203).

2⁷⁹⁵⁴⁰ 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 79540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86436).

79540 is an abundant number, since it is smaller than the sum of its proper divisors (93332).

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

79540 is a wasteful number, since it uses less digits than its factorization.

79540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147 (or 145 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 25.

The square root of 79540 is about 282.0283673675. The cubic root of 79540 is about 43.0059483388.

The spelling of 79540 in words is "seventy-nine thousand, five hundred forty".