66240421 has 16 divisors (see below), whose sum is σ = 73684800. Its totient is φ = 59165568.

The previous prime is 66240401. The next prime is 66240439. The reversal of 66240421 is 12404266.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66240421 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 (66240401) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50745 + ... + 52033.

It is an arithmetic number, because the mean of its divisors is an integer number (4605300).

Almost surely, 2^66240421 is an apocalyptic number.

It is an amenable number.

66240421 is a deficient number, since it is larger than the sum of its proper divisors (7444379).

66240421 is a wasteful number, since it uses less digits than its factorization.

66240421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1428.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 66240421 is about 8138.8218434857. The cubic root of 66240421 is about 404.6141139749.

Adding to 66240421 its reverse (12404266), we get a palindrome (78644687).

The spelling of 66240421 in words is "sixty-six million, two hundred forty thousand, four hundred twenty-one".