20211099999966 has 80 divisors (see below), whose sum is σ = 45568805990400. Its totient is φ = 6695253372240.

The previous prime is 20211099999917. The next prime is 20211099999967. The reversal of 20211099999966 is 66999999011202.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 20211099999894 and 20211099999903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20211099999967) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 129754311 + ... + 129909981.

It is an arithmetic number, because the mean of its divisors is an integer number (569610074880).

Almost surely, 2^{20211099999966} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20211099999966, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22784402995200).

20211099999966 is an abundant number, since it is smaller than the sum of its proper divisors (25357705990434).

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

20211099999966 is a wasteful number, since it uses less digits than its factorization.

20211099999966 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160651 (or 160642 counting only the distinct ones).

The product of its (nonzero) digits is 76527504, while the sum is 72.

The spelling of 20211099999966 in words is "twenty trillion, two hundred eleven billion, ninety-nine million, nine hundred ninety-nine thousand, nine hundred sixty-six".