79661 has 4 divisors (see below), whose sum is σ = 81852. Its totient is φ = 77472.

The previous prime is 79657. The next prime is 79669. The reversal of 79661 is 16697.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16697 = 59 ⋅283.

It can be written as a sum of positive squares in 2 ways, for example, as 37636 + 42025 = 194^2 + 205^2 .

It is a cyclic number.

It is not a de Polignac number, because 79661 - 2² = 79657 is a prime.

It is a Duffinian number.

It is a plaindrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79669) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1040 + ... + 1113.

It is an arithmetic number, because the mean of its divisors is an integer number (20463).

2⁷⁹⁶⁶¹ is an apocalyptic number.

It is an amenable number.

79661 is a deficient number, since it is larger than the sum of its proper divisors (2191).

79661 is a wasteful number, since it uses less digits than its factorization.

79661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2190.

The product of its digits is 2268, while the sum is 29.

The square root of 79661 is about 282.2428032741. The cubic root of 79661 is about 43.0277448490.

The spelling of 79661 in words is "seventy-nine thousand, six hundred sixty-one".