87661 has 6 divisors (see below), whose sum is σ = 102030. Its totient is φ = 75096.

The previous prime is 87649. The next prime is 87671. The reversal of 87661 is 16678.

It can be written as a sum of positive squares in only one way, i.e., 86436 + 1225 = 294^2 + 35^2 .

It is not a de Polignac number, because 87661 - 2⁵ = 87629 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (87631) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 846 + ... + 943.

It is an arithmetic number, because the mean of its divisors is an integer number (17005).

2⁸⁷⁶⁶¹ is an apocalyptic number.

It is an amenable number.

87661 is a deficient number, since it is larger than the sum of its proper divisors (14369).

87661 is a wasteful number, since it uses less digits than its factorization.

87661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1803 (or 1796 counting only the distinct ones).

The product of its digits is 2016, while the sum is 28.

The square root of 87661 is about 296.0760037558. The cubic root of 87661 is about 44.4224124597.

The spelling of 87661 in words is "eighty-seven thousand, six hundred sixty-one".