66646899 has 12 divisors (see below), whose sum is σ = 105019512. Its totient is φ = 40392000.

The previous prime is 66646897. The next prime is 66646903. The reversal of 66646899 is 99864666.

It is a happy number.

It is not a de Polignac number, because 66646899 - 2¹ = 66646897 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66646897) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 336502 + ... + 336699.

It is an arithmetic number, because the mean of its divisors is an integer number (8751626).

Almost surely, 2^66646899 is an apocalyptic number.

66646899 is a deficient number, since it is larger than the sum of its proper divisors (38372613).

66646899 is a wasteful number, since it uses less digits than its factorization.

66646899 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 673218 (or 673215 counting only the distinct ones).

The product of its digits is 3359232, while the sum is 54.

The square root of 66646899 is about 8163.7552021113. The cubic root of 66646899 is about 405.4400520959.

The spelling of 66646899 in words is "sixty-six million, six hundred forty-six thousand, eight hundred ninety-nine".