20105561523 has 16 divisors (see below), whose sum is σ = 27502070400. Its totient is φ = 13060805184.

The previous prime is 20105561519. The next prime is 20105561543. The reversal of 20105561523 is 32516550102.

It is a happy number.

It is not a de Polignac number, because 20105561523 - 2² = 20105561519 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20105561543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 534873 + ... + 571226.

It is an arithmetic number, because the mean of its divisors is an integer number (1718879400).

Almost surely, 2^20105561523 is an apocalyptic number.

20105561523 is a deficient number, since it is larger than the sum of its proper divisors (7396508877).

20105561523 is a wasteful number, since it uses less digits than its factorization.

20105561523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1106258.

The product of its (nonzero) digits is 9000, while the sum is 30.

The spelling of 20105561523 in words is "twenty billion, one hundred five million, five hundred sixty-one thousand, five hundred twenty-three".