61909 has 2 divisors, whose sum is σ = 61910.
Its totient is φ = 61908.
The previous prime is 61879. The next prime is 61927. The reversal of 61909 is 90916.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 61009 + 900 = 247^2 + 30^2
It is a cyclic number.
It is not a de Polignac number, because 61909 - 27 = 61781 is a prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (61949) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 30954 + 30955.
It is an arithmetic number, because the mean of its divisors is an integer number (30955).
261909 is an apocalyptic number.
It is an amenable number.
61909 is a deficient number, since it is larger than the sum of its proper divisors (1).
61909 is an equidigital number, since it uses as much as digits as its factorization.
61909 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 486, while the sum is 25.
The square root of 61909 is about 248.8151924622.
The cubic root of 61909 is about 39.5595427370.
The spelling of 61909 in words is "sixty-one thousand, nine hundred nine".