66211689 has 16 divisors (see below), whose sum is σ = 90218880. Its totient is φ = 43182720.

The previous prime is 66211643. The next prime is 66211697. The reversal of 66211689 is 98611266.

It is not a de Polignac number, because 66211689 - 2¹⁷ = 66080617 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66211609) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28047 + ... + 30315.

It is an arithmetic number, because the mean of its divisors is an integer number (5638680).

Almost surely, 2^66211689 is an apocalyptic number.

It is an amenable number.

66211689 is a deficient number, since it is larger than the sum of its proper divisors (24007191).

66211689 is a wasteful number, since it uses less digits than its factorization.

66211689 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2480.

The product of its digits is 31104, while the sum is 39.

The square root of 66211689 is about 8137.0565316950. The cubic root of 66211689 is about 404.5556046146. Note that the first 3 decimals are identical.

The spelling of 66211689 in words is "sixty-six million, two hundred eleven thousand, six hundred eighty-nine".