66189649 has 2 divisors, whose sum is σ = 66189650. Its totient is φ = 66189648.

The previous prime is 66189623. The next prime is 66189659. The reversal of 66189649 is 94698166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57380625 + 8809024 = 7575^2 + 2968^2 .

It is a cyclic number.

It is not a de Polignac number, because 66189649 - 2¹³ = 66181457 is a prime.

It is not a weakly prime, because it can be changed into another prime (66189659) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33094824 + 33094825.

It is an arithmetic number, because the mean of its divisors is an integer number (33094825).

Almost surely, 2^66189649 is an apocalyptic number.

It is an amenable number.

66189649 is a deficient number, since it is larger than the sum of its proper divisors (1).

66189649 is an equidigital number, since it uses as much as digits as its factorization.

66189649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 559872, while the sum is 49.

The square root of 66189649 is about 8135.7021208990. The cubic root of 66189649 is about 404.5107112573.

The spelling of 66189649 in words is "sixty-six million, one hundred eighty-nine thousand, six hundred forty-nine".