20013721335666 has 32 divisors (see below), whose sum is σ = 45084182013120. Its totient is φ = 6579853588512.

The previous prime is 20013721335649. The next prime is 20013721335667. The reversal of 20013721335666 is 66653312731002.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (20013721335667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2538519820 + ... + 2538527703.

It is an arithmetic number, because the mean of its divisors is an integer number (1408880687910).

Almost surely, 2^{20013721335666} is an apocalyptic number.

20013721335666 is an abundant number, since it is smaller than the sum of its proper divisors (25070460677454).

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

20013721335666 is a wasteful number, since it uses less digits than its factorization.

20013721335666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5077047607 (or 5077047601 counting only the distinct ones).

The product of its (nonzero) digits is 816480, while the sum is 45.

The spelling of 20013721335666 in words is "twenty trillion, thirteen billion, seven hundred twenty-one million, three hundred thirty-five thousand, six hundred sixty-six".