66011661 has 12 divisors (see below), whose sum is σ = 95642560. Its totient is φ = 43872840.

The previous prime is 66011657. The next prime is 66011711. The reversal of 66011661 is 16611066.

It is not a de Polignac number, because 66011661 - 2² = 66011657 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66011161) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8101 + ... + 14058.

Almost surely, 2^66011661 is an apocalyptic number.

It is an amenable number.

66011661 is a deficient number, since it is larger than the sum of its proper divisors (29630899).

66011661 is a wasteful number, since it uses less digits than its factorization.

66011661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22496 (or 22493 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 66011661 is about 8124.7560578764. The cubic root of 66011661 is about 404.1478011151.

It can be divided in two parts, 660 and 11661, that added together give a palindrome (12321).

The spelling of 66011661 in words is "sixty-six million, eleven thousand, six hundred sixty-one".