61999 has 8 divisors (see below), whose sum is σ = 75168.
Its totient is φ = 49920.
The previous prime is 61991. The next prime is 62003. The reversal of 61999 is 99916.
It is a happy number.
61999 is nontrivially palindromic in base 16.
It is a sphenic number, since it is the product of 3 distinct primes.
It is a cyclic number.
It is not a de Polignac number, because 61999 - 23 = 61991 is a prime.
It is a Duffinian number.
61999 is a modest number, since divided by 999 gives 61 as remainder.
61999 is a lucky number.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (61991) by changing a digit.
It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142 + ... + 379.
It is an arithmetic number, because the mean of its divisors is an integer number (9396).
261999 is an apocalyptic number.
61999 is a deficient number, since it is larger than the sum of its proper divisors (13169).
61999 is a wasteful number, since it uses less digits than its factorization.
61999 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 545.
The product of its digits is 4374, while the sum is 34.
The square root of 61999 is about 248.9959839034.
The cubic root of 61999 is about 39.5787033058.
The spelling of 61999 in words is "sixty-one thousand, nine hundred ninety-nine".