61591 has 4 divisors (see below), whose sum is σ = 65232. Its totient is φ = 57952.

The previous prime is 61583. The next prime is 61603. The reversal of 61591 is 19516.

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

It is a cyclic number.

It is not a de Polignac number, because 61591 - 2³ = 61583 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61511) 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, 1795 + ... + 1828.

It is an arithmetic number, because the mean of its divisors is an integer number (16308).

2⁶¹⁵⁹¹ is an apocalyptic number.

61591 is a deficient number, since it is larger than the sum of its proper divisors (3641).

61591 is a wasteful number, since it uses less digits than its factorization.

61591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3640.

The product of its digits is 270, while the sum is 22.

The square root of 61591 is about 248.1753412408. The cubic root of 61591 is about 39.4916929602.

The spelling of 61591 in words is "sixty-one thousand, five hundred ninety-one".