61865 has 4 divisors (see below), whose sum is σ = 74244. Its totient is φ = 49488.

The previous prime is 61861. The next prime is 61871. The reversal of 61865 is 56816.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 26896 + 34969 = 164^2 + 187^2 .

It is a cyclic number.

It is not a de Polignac number, because 61865 - 2² = 61861 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (61861) 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, 6182 + ... + 6191.

It is an arithmetic number, because the mean of its divisors is an integer number (18561).

2⁶¹⁸⁶⁵ is an apocalyptic number.

It is an amenable number.

61865 is a deficient number, since it is larger than the sum of its proper divisors (12379).

61865 is a wasteful number, since it uses less digits than its factorization.

61865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12378.

The product of its digits is 1440, while the sum is 26.

The square root of 61865 is about 248.7267577081. The cubic root of 61865 is about 39.5501685889.

The spelling of 61865 in words is "sixty-one thousand, eight hundred sixty-five".