66699877899666 has 64 divisors (see below), whose sum is σ = 147945466598400. Its totient is φ = 19876333780800.

The previous prime is 66699877899653. The next prime is 66699877899701.

66699877899666 is nontrivially palindromic in base 10.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16360425 + ... + 20026563.

It is an arithmetic number, because the mean of its divisors is an integer number (2311647915600).

Almost surely, 2^{66699877899666} is an apocalyptic number.

66699877899666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 66699877899666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (73972733299200).

66699877899666 is an abundant number, since it is smaller than the sum of its proper divisors (81245588698734).

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

66699877899666 is a wasteful number, since it uses less digits than its factorization.

66699877899666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3670735.

The product of its digits is 959961010176, while the sum is 102.

The spelling of 66699877899666 in words is "sixty-six trillion, six hundred ninety-nine billion, eight hundred seventy-seven million, eight hundred ninety-nine thousand, six hundred sixty-six".