20111423505 has 16 divisors (see below), whose sum is σ = 32496876864. Its totient is φ = 10619892800.

The previous prime is 20111423447. The next prime is 20111423573. The reversal of 20111423505 is 50532411102.

It is a happy number.

It is not a de Polignac number, because 20111423505 - 2⁶ = 20111423441 is a prime.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 6635919 + ... + 6638948.

It is an arithmetic number, because the mean of its divisors is an integer number (2031054804).

Almost surely, 2^20111423505 is an apocalyptic number.

It is an amenable number.

20111423505 is a deficient number, since it is larger than the sum of its proper divisors (12385453359).

20111423505 is a wasteful number, since it uses less digits than its factorization.

20111423505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13274976.

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 20111423505 its reverse (50532411102), we get a palindrome (70643834607).

It can be divided in two parts, 2011 and 1423505, that added together give a triangular number (1425516 = T₁₆₈₈).

The spelling of 20111423505 in words is "twenty billion, one hundred eleven million, four hundred twenty-three thousand, five hundred five".