66609663 has 4 divisors (see below), whose sum is σ = 88812888. Its totient is φ = 44406440.

The previous prime is 66609661. The next prime is 66609677. The reversal of 66609663 is 36690666.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 66609663 - 2¹ = 66609661 is a prime.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66609661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11101608 + ... + 11101613.

It is an arithmetic number, because the mean of its divisors is an integer number (22203222).

Almost surely, 2^66609663 is an apocalyptic number.

66609663 is a deficient number, since it is larger than the sum of its proper divisors (22203225).

66609663 is a wasteful number, since it uses less digits than its factorization.

66609663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22203224.

The product of its (nonzero) digits is 209952, while the sum is 42.

The square root of 66609663 is about 8161.4743153428. The cubic root of 66609663 is about 405.3645308115.

The spelling of 66609663 in words is "sixty-six million, six hundred nine thousand, six hundred sixty-three".