61669609 has 3 divisors (see below), whose sum is σ = 61677463. Its totient is φ = 61661756.

The previous prime is 61669607. The next prime is 61669667. The reversal of 61669609 is 90696616.

The square root of 61669609 is 7853.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 1265625 + 60403984 = 1125^2 + 7772^2 .

It is not a de Polignac number, because 61669609 - 2¹ = 61669607 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (61669607) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 3927 + ... + 11779.

Almost surely, 2^61669609 is an apocalyptic number.

61669609 is the 7853-rd square number.

61669609 is the 3927-th centered octagonal number.

It is an amenable number.

61669609 is a deficient number, since it is larger than the sum of its proper divisors (7854).

61669609 is an frugal number, since it uses more digits than its factorization.

61669609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15706 (or 7853 counting only the distinct ones).

The product of its (nonzero) digits is 104976, while the sum is 43.

The cubic root of 61669609 is about 395.0848698691.

Multiplying 61669609 by its product of nonzero digits (104976), we get a square (6473828874384 = 2544372²).

It can be divided in two parts, 616 and 69609, that added together give a square (70225 = 265²).

The spelling of 61669609 in words is "sixty-one million, six hundred sixty-nine thousand, six hundred nine".