61666651 has 2 divisors, whose sum is σ = 61666652. Its totient is φ = 61666650.

The previous prime is 61666639. The next prime is 61666681. The reversal of 61666651 is 15666616.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 61666651 - 2⁷ = 61666523 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 61666651.

It is not a weakly prime, because it can be changed into another prime (61666681) 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 as a sum of consecutive naturals, namely, 30833325 + 30833326.

It is an arithmetic number, because the mean of its divisors is an integer number (30833326).

Almost surely, 2^61666651 is an apocalyptic number.

61666651 is a deficient number, since it is larger than the sum of its proper divisors (1).

61666651 is an equidigital number, since it uses as much as digits as its factorization.

61666651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 38880, while the sum is 37.

The square root of 61666651 is about 7852.8116620737. The cubic root of 61666651 is about 395.0785529827.

The spelling of 61666651 in words is "sixty-one million, six hundred sixty-six thousand, six hundred fifty-one".