61009 has 9 divisors (see below), whose sum is σ = 69723. Its totient is φ = 53352.

The previous prime is 61007. The next prime is 61027. The reversal of 61009 is 90016.

61009 = T₂₄₆ + T₂₄₇.

The square root of 61009 is 247.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 9025 + 51984 = 95^2 + 228^2 .

It is not a de Polignac number, because 61009 - 2¹ = 61007 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 16.

It is a junction number, because it is equal to n+sod(n) for n = 60983 and 61001.

It is not an unprimeable number, because it can be changed into a prime (61001) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 3202 + ... + 3220.

It is an arithmetic number, because the mean of its divisors is an integer number (7747).

2⁶¹⁰⁰⁹ is an apocalyptic number.

61009 is the 247-th square number.

61009 is the 124-th centered octagonal number.

It is an amenable number.

61009 is a deficient number, since it is larger than the sum of its proper divisors (8714).

61009 is a wasteful number, since it uses less digits than its factorization.

61009 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64 (or 32 counting only the distinct ones).

The product of its (nonzero) digits is 54, while the sum is 16.

The cubic root of 61009 is about 39.3669077180.

Multiplying 61009 by its sum of digits (16), we get a square (976144 = 988²).

The spelling of 61009 in words is "sixty-one thousand, nine".