20506656553 has 8 divisors (see below), whose sum is σ = 20666501856. Its totient is φ = 20346861600.

The previous prime is 20506656497. The next prime is 20506656563. The reversal of 20506656553 is 35565660502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20506656553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20506656563) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1566925 + ... + 1579957.

It is an arithmetic number, because the mean of its divisors is an integer number (2583312732).

Almost surely, 2^20506656553 is an apocalyptic number.

It is an amenable number.

20506656553 is a deficient number, since it is larger than the sum of its proper divisors (159845303).

20506656553 is a wasteful number, since it uses less digits than its factorization.

20506656553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25175.

The product of its (nonzero) digits is 810000, while the sum is 43.

The spelling of 20506656553 in words is "twenty billion, five hundred six million, six hundred fifty-six thousand, five hundred fifty-three".