61666647 has 24 divisors (see below), whose sum is σ = 100684800. Its totient is φ = 33381936.

The previous prime is 61666639. The next prime is 61666651. The reversal of 61666647 is 74666616.

It is not a de Polignac number, because 61666647 - 2³ = 61666639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 61666599 and 61666608.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61666697) 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 23 ways as a sum of consecutive naturals, for example, 8247 + ... + 13832.

It is an arithmetic number, because the mean of its divisors is an integer number (4195200).

Almost surely, 2^61666647 is an apocalyptic number.

61666647 is a deficient number, since it is larger than the sum of its proper divisors (39018153).

61666647 is a wasteful number, since it uses less digits than its factorization.

61666647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22115 (or 22108 counting only the distinct ones).

The product of its digits is 217728, while the sum is 42.

The square root of 61666647 is about 7852.8114073878. The cubic root of 61666647 is about 395.0785444405.

The spelling of 61666647 in words is "sixty-one million, six hundred sixty-six thousand, six hundred forty-seven".