66326621 has 4 divisors (see below), whose sum is σ = 66518112. Its totient is φ = 66135132.

The previous prime is 66326591. The next prime is 66326647. The reversal of 66326621 is 12662366.

66326621 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12662366 = 2 ⋅6331183.

It is a cyclic number.

It is not a de Polignac number, because 66326621 - 2¹⁸ = 66064477 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66326921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 95225 + ... + 95918.

It is an arithmetic number, because the mean of its divisors is an integer number (16629528).

Almost surely, 2^66326621 is an apocalyptic number.

It is an amenable number.

66326621 is a deficient number, since it is larger than the sum of its proper divisors (191491).

66326621 is a wasteful number, since it uses less digits than its factorization.

66326621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191490.

The product of its digits is 15552, while the sum is 32.

The square root of 66326621 is about 8144.1157285490. The cubic root of 66326621 is about 404.7895487422.

Adding to 66326621 its reverse (12662366), we get a palindrome (78988987).

The spelling of 66326621 in words is "sixty-six million, three hundred twenty-six thousand, six hundred twenty-one".