66644999 has 2 divisors, whose sum is σ = 66645000. Its totient is φ = 66644998.

The previous prime is 66644971. The next prime is 66645031. The reversal of 66644999 is 99944666.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66644999 is a prime.

It is a Chen prime.

It is a zygodrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 66644999.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66644959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33322499 + 33322500.

It is an arithmetic number, because the mean of its divisors is an integer number (33322500).

Almost surely, 2^66644999 is an apocalyptic number.

66644999 is a deficient number, since it is larger than the sum of its proper divisors (1).

66644999 is an equidigital number, since it uses as much as digits as its factorization.

66644999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2519424, while the sum is 53.

The square root of 66644999 is about 8163.6388332655. The cubic root of 66644999 is about 405.4361992364.

The spelling of 66644999 in words is "sixty-six million, six hundred forty-four thousand, nine hundred ninety-nine".