20566666633 has 4 divisors (see below), whose sum is σ = 20598162948. Its totient is φ = 20535170320.

The previous prime is 20566666621. The next prime is 20566666667. The reversal of 20566666633 is 33666666502.

It is a happy number.

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 13250772544 + 7315894089 = 115112^2 + 85533^2 .

It is a cyclic number.

It is not a de Polignac number, because 20566666633 - 2²¹ = 20564569481 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20566666613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15747178 + ... + 15748483.

It is an arithmetic number, because the mean of its divisors is an integer number (5149540737).

Almost surely, 2^20566666633 is an apocalyptic number.

It is an amenable number.

20566666633 is a deficient number, since it is larger than the sum of its proper divisors (31496315).

20566666633 is an equidigital number, since it uses as much as digits as its factorization.

20566666633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31496314.

The product of its (nonzero) digits is 4199040, while the sum is 49.

The spelling of 20566666633 in words is "twenty billion, five hundred sixty-six million, six hundred sixty-six thousand, six hundred thirty-three".