61666493 has 4 divisors (see below), whose sum is σ = 70476000. Its totient is φ = 52856988.

The previous prime is 61666487. The next prime is 61666523. The reversal of 61666493 is 39466616.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 61666493 - 2¹² = 61662397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 61666493.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (61666403) 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 3 ways as a sum of consecutive naturals, for example, 4404743 + ... + 4404756.

It is an arithmetic number, because the mean of its divisors is an integer number (17619000).

Almost surely, 2^61666493 is an apocalyptic number.

It is an amenable number.

61666493 is a deficient number, since it is larger than the sum of its proper divisors (8809507).

61666493 is an equidigital number, since it uses as much as digits as its factorization.

61666493 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8809506.

The product of its digits is 139968, while the sum is 41.

The square root of 61666493 is about 7852.8016019762. The cubic root of 61666493 is about 395.0782155639.

The spelling of 61666493 in words is "sixty-one million, six hundred sixty-six thousand, four hundred ninety-three".