20561100066001 has 4 divisors (see below), whose sum is σ = 22430290981104. Its totient is φ = 18691909150900.

The previous prime is 20561100065941. The next prime is 20561100066029. The reversal of 20561100066001 is 10066000116502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20561100066001 - 2⁹ = 20561100065489 is a prime.

It is a super-2 number, since 2×20561100066001² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20561100066301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 934595457535 + ... + 934595457556.

It is an arithmetic number, because the mean of its divisors is an integer number (5607572745276).

Almost surely, 2^{20561100066001} is an apocalyptic number.

It is an amenable number.

20561100066001 is a deficient number, since it is larger than the sum of its proper divisors (1869190915103).

20561100066001 is a wasteful number, since it uses less digits than its factorization.

20561100066001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1869190915102.

The product of its (nonzero) digits is 2160, while the sum is 28.

The spelling of 20561100066001 in words is "twenty trillion, five hundred sixty-one billion, one hundred million, sixty-six thousand, one".