61561709 has 8 divisors (see below), whose sum is σ = 71108928. Its totient is φ = 52672960.

The previous prime is 61561663. The next prime is 61561727. The reversal of 61561709 is 90716516.

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 61561709 - 2²⁰ = 60513133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61566709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164417 + ... + 164790.

It is an arithmetic number, because the mean of its divisors is an integer number (8888616).

Almost surely, 2^61561709 is an apocalyptic number.

It is an amenable number.

61561709 is a deficient number, since it is larger than the sum of its proper divisors (9547219).

61561709 is a wasteful number, since it uses less digits than its factorization.

61561709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329235.

The product of its (nonzero) digits is 11340, while the sum is 35.

The square root of 61561709 is about 7846.1270063644. The cubic root of 61561709 is about 394.8543157673.

The spelling of 61561709 in words is "sixty-one million, five hundred sixty-one thousand, seven hundred nine".