66241621 has 2 divisors, whose sum is σ = 66241622. Its totient is φ = 66241620.

The previous prime is 66241583. The next prime is 66241631. The reversal of 66241621 is 12614266.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50552100 + 15689521 = 7110^2 + 3961^2 .

It is a cyclic number.

It is not a de Polignac number, because 66241621 - 2¹⁷ = 66110549 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66241621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66241631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33120810 + 33120811.

It is an arithmetic number, because the mean of its divisors is an integer number (33120811).

Almost surely, 2^66241621 is an apocalyptic number.

It is an amenable number.

66241621 is a deficient number, since it is larger than the sum of its proper divisors (1).

66241621 is an equidigital number, since it uses as much as digits as its factorization.

66241621 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3456, while the sum is 28.

The square root of 66241621 is about 8138.8955638956. The cubic root of 66241621 is about 404.6165572666.

Adding to 66241621 its reverse (12614266), we get a palindrome (78855887).

The spelling of 66241621 in words is "sixty-six million, two hundred forty-one thousand, six hundred twenty-one".