61639 has 4 divisors (see below), whose sum is σ = 62856. Its totient is φ = 60424.

The previous prime is 61637. The next prime is 61643. The reversal of 61639 is 93616.

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 61639 - 2¹ = 61637 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61631) 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, 529 + ... + 634.

It is an arithmetic number, because the mean of its divisors is an integer number (15714).

2⁶¹⁶³⁹ is an apocalyptic number.

61639 is a deficient number, since it is larger than the sum of its proper divisors (1217).

61639 is a wasteful number, since it uses less digits than its factorization.

61639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1216.

The product of its digits is 972, while the sum is 25.

The square root of 61639 is about 248.2720282271. The cubic root of 61639 is about 39.5019493777.

The spelling of 61639 in words is "sixty-one thousand, six hundred thirty-nine".