20556005611 has 4 divisors (see below), whose sum is σ = 20622963592. Its totient is φ = 20489047632.

The previous prime is 20556005597. The next prime is 20556005629. The reversal of 20556005611 is 11650065502.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20556005611 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20556005641) 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, 33478530 + ... + 33479143.

It is an arithmetic number, because the mean of its divisors is an integer number (5155740898).

Almost surely, 2^20556005611 is an apocalyptic number.

20556005611 is a deficient number, since it is larger than the sum of its proper divisors (66957981).

20556005611 is an equidigital number, since it uses as much as digits as its factorization.

20556005611 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66957980.

The product of its (nonzero) digits is 9000, while the sum is 31.

The spelling of 20556005611 in words is "twenty billion, five hundred fifty-six million, five thousand, six hundred eleven".