66240621 has 24 divisors (see below), whose sum is σ = 100900800. Its totient is φ = 41792256.

The previous prime is 66240613. The next prime is 66240673. The reversal of 66240621 is 12604266.

It is a happy number.

It is not a de Polignac number, because 66240621 - 2³ = 66240613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66240121) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18430 + ... + 21728.

It is an arithmetic number, because the mean of its divisors is an integer number (4204200).

Almost surely, 2^66240621 is an apocalyptic number.

It is an amenable number.

66240621 is a deficient number, since it is larger than the sum of its proper divisors (34660179).

66240621 is a wasteful number, since it uses less digits than its factorization.

66240621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3425 (or 3422 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 66240621 is about 8138.8341302671. The cubic root of 66240621 is about 404.6145211923.

Adding to 66240621 its reverse (12604266), we get a palindrome (78844887).

The spelling of 66240621 in words is "sixty-six million, two hundred forty thousand, six hundred twenty-one".