66613649 has 2 divisors, whose sum is σ = 66613650. Its totient is φ = 66613648.

The previous prime is 66613627. The next prime is 66613693. The reversal of 66613649 is 94631666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60949249 + 5664400 = 7807^2 + 2380^2 .

It is a cyclic number.

It is not a de Polignac number, because 66613649 - 2¹⁶ = 66548113 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66613619) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33306824 + 33306825.

It is an arithmetic number, because the mean of its divisors is an integer number (33306825).

Almost surely, 2^66613649 is an apocalyptic number.

It is an amenable number.

66613649 is a deficient number, since it is larger than the sum of its proper divisors (1).

66613649 is an equidigital number, since it uses as much as digits as its factorization.

66613649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 139968, while the sum is 41.

The square root of 66613649 is about 8161.7185077654. The cubic root of 66613649 is about 405.3726164791.

The spelling of 66613649 in words is "sixty-six million, six hundred thirteen thousand, six hundred forty-nine".