66613031666 has 4 divisors (see below), whose sum is σ = 99919547502. Its totient is φ = 33306515832.

The previous prime is 66613031657. The next prime is 66613031671.

It is a happy number.

66613031666 is nontrivially palindromic in base 10.

66613031666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It can be written as a sum of positive squares in only one way, i.e., 36555528025 + 30057503641 = 191195^2 + 173371^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 16653257915 + ... + 16653257918.

Almost surely, 2^66613031666 is an apocalyptic number.

66613031666 is a deficient number, since it is larger than the sum of its proper divisors (33306515836).

66613031666 is a wasteful number, since it uses less digits than its factorization.

66613031666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33306515835.

The product of its (nonzero) digits is 419904, while the sum is 44.

It can be divided in two parts, 666130 and 31666, that added together give a palindrome (697796).

The spelling of 66613031666 in words is "sixty-six billion, six hundred thirteen million, thirty-one thousand, six hundred sixty-six".