66209947 has 2 divisors, whose sum is σ = 66209948. Its totient is φ = 66209946.

The previous prime is 66209933. The next prime is 66209963. The reversal of 66209947 is 74990266.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66209947 - 2¹⁵ = 66177179 is a prime.

It is not a weakly prime, because it can be changed into another prime (66200947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33104973 + 33104974.

It is an arithmetic number, because the mean of its divisors is an integer number (33104974).

Almost surely, 2^66209947 is an apocalyptic number.

66209947 is a deficient number, since it is larger than the sum of its proper divisors (1).

66209947 is an equidigital number, since it uses as much as digits as its factorization.

66209947 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 163296, while the sum is 43.

The square root of 66209947 is about 8136.9494898273. The cubic root of 66209947 is about 404.5520566910.

The spelling of 66209947 in words is "sixty-six million, two hundred nine thousand, nine hundred forty-seven".