20201864661 has 12 divisors (see below), whose sum is σ = 31833241440. Its totient is φ = 12243554280.

The previous prime is 20201864647. The next prime is 20201864671. The reversal of 20201864661 is 16646810202.

20201864661 is a `hidden beast` number, since 2 + 0 + 2 + 0 + 1 + 8 + 646 + 6 + 1 = 666.

It is not a de Polignac number, because 20201864661 - 2⁹ = 20201864149 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20201864671) 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, 102029521 + ... + 102029718.

It is an arithmetic number, because the mean of its divisors is an integer number (2652770120).

Almost surely, 2^20201864661 is an apocalyptic number.

It is an amenable number.

20201864661 is a deficient number, since it is larger than the sum of its proper divisors (11631376779).

20201864661 is a wasteful number, since it uses less digits than its factorization.

20201864661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 204059256 (or 204059253 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

It can be divided in two parts, 2020 and 1864661, that added together give a palindrome (1866681).

The spelling of 20201864661 in words is "twenty billion, two hundred one million, eight hundred sixty-four thousand, six hundred sixty-one".