61391 has 4 divisors (see below), whose sum is σ = 66984. Its totient is φ = 55800.

The previous prime is 61381. The next prime is 61403. The reversal of 61391 is 19316.

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 61391 - 2¹⁴ = 45007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2780 + ... + 2801.

It is an arithmetic number, because the mean of its divisors is an integer number (16746).

2⁶¹³⁹¹ is an apocalyptic number.

61391 is a deficient number, since it is larger than the sum of its proper divisors (5593).

61391 is a wasteful number, since it uses less digits than its factorization.

61391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5592.

The product of its digits is 162, while the sum is 20.

The square root of 61391 is about 247.7720726797. The cubic root of 61391 is about 39.4489004348.

The spelling of 61391 in words is "sixty-one thousand, three hundred ninety-one".