66305621 has 8 divisors (see below), whose sum is σ = 68557824. Its totient is φ = 64060560.

The previous prime is 66305609. The next prime is 66305633. The reversal of 66305621 is 12650366.

It is an interprime number because it is at equal distance from previous prime (66305609) and next prime (66305633).

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 66305621 - 2¹⁸ = 66043477 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66305521) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22580 + ... + 25346.

It is an arithmetic number, because the mean of its divisors is an integer number (8569728).

Almost surely, 2^66305621 is an apocalyptic number.

It is an amenable number.

66305621 is a deficient number, since it is larger than the sum of its proper divisors (2252203).

66305621 is a wasteful number, since it uses less digits than its factorization.

66305621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3571.

The product of its (nonzero) digits is 6480, while the sum is 29.

The square root of 66305621 is about 8142.8263520721. The cubic root of 66305621 is about 404.7468234247.

Adding to 66305621 its reverse (12650366), we get a palindrome (78955987).

The spelling of 66305621 in words is "sixty-six million, three hundred five thousand, six hundred twenty-one".