20561105553 has 32 divisors (see below), whose sum is σ = 28847923200. Its totient is φ = 13001208000.

The previous prime is 20561105527. The next prime is 20561105567. The reversal of 20561105553 is 35550116502.

It is not a de Polignac number, because 20561105553 - 2¹⁴ = 20561089169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20561105573) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7719700 + ... + 7722362.

It is an arithmetic number, because the mean of its divisors is an integer number (901497600).

Almost surely, 2^20561105553 is an apocalyptic number.

20561105553 is a gapful number since it is divisible by the number (23) formed by its first and last digit.

It is an amenable number.

20561105553 is a deficient number, since it is larger than the sum of its proper divisors (8286817647).

20561105553 is a wasteful number, since it uses less digits than its factorization.

20561105553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3589.

The product of its (nonzero) digits is 22500, while the sum is 33.

The spelling of 20561105553 in words is "twenty billion, five hundred sixty-one million, one hundred five thousand, five hundred fifty-three".