66661698 has 32 divisors (see below), whose sum is σ = 137620224. Its totient is φ = 21514752.

The previous prime is 66661669. The next prime is 66661733. The reversal of 66661698 is 89616666.

It is a happy number.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26136 + ... + 28572.

It is an arithmetic number, because the mean of its divisors is an integer number (4300632).

Almost surely, 2^66661698 is an apocalyptic number.

66661698 is an abundant number, since it is smaller than the sum of its proper divisors (70958526).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66661698 is a wasteful number, since it uses less digits than its factorization.

66661698 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2586.

The product of its digits is 559872, while the sum is 48.

The square root of 66661698 is about 8164.6615361569. The cubic root of 66661698 is about 405.4700593099.

The spelling of 66661698 in words is "sixty-six million, six hundred sixty-one thousand, six hundred ninety-eight".