20666661241 has 4 divisors (see below), whose sum is σ = 20756908900. Its totient is φ = 20576413584.

The previous prime is 20666661229. The next prime is 20666661271. The reversal of 20666661241 is 14216666602.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13275648400 + 7391012841 = 115220^2 + 85971^2 .

It is a cyclic number.

It is not a de Polignac number, because 20666661241 - 2¹⁵ = 20666628473 is a prime.

It is a super-2 number, since 2×20666661241² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20666661194 and 20666661203.

It is not an unprimeable number, because it can be changed into a prime (20666661271) 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, 45123486 + ... + 45123943.

It is an arithmetic number, because the mean of its divisors is an integer number (5189227225).

Almost surely, 2^20666661241 is an apocalyptic number.

It is an amenable number.

20666661241 is a deficient number, since it is larger than the sum of its proper divisors (90247659).

20666661241 is an equidigital number, since it uses as much as digits as its factorization.

20666661241 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90247658.

The product of its (nonzero) digits is 124416, while the sum is 40.

The spelling of 20666661241 in words is "twenty billion, six hundred sixty-six million, six hundred sixty-one thousand, two hundred forty-one".