66636649 has 2 divisors, whose sum is σ = 66636650. Its totient is φ = 66636648.

The previous prime is 66636643. The next prime is 66636677. The reversal of 66636649 is 94663666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 52998400 + 13638249 = 7280^2 + 3693^2 .

It is a cyclic number.

It is not a de Polignac number, because 66636649 - 2³ = 66636641 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66636599 and 66636608.

It is not a weakly prime, because it can be changed into another prime (66636641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33318324 + 33318325.

It is an arithmetic number, because the mean of its divisors is an integer number (33318325).

Almost surely, 2^66636649 is an apocalyptic number.

It is an amenable number.

66636649 is a deficient number, since it is larger than the sum of its proper divisors (1).

66636649 is an equidigital number, since it uses as much as digits as its factorization.

66636649 is an evil number, because the sum of its binary digits is even.

The product of its digits is 839808, while the sum is 46.

The square root of 66636649 is about 8163.1274031464. The cubic root of 66636649 is about 405.4192660645.

The spelling of 66636649 in words is "sixty-six million, six hundred thirty-six thousand, six hundred forty-nine".