21111034523 has 4 divisors (see below), whose sum is σ = 21112100688. Its totient is φ = 21109968360.

The previous prime is 21111034481. The next prime is 21111034531. The reversal of 21111034523 is 32543011112.

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

It is a cyclic number.

It is not a de Polignac number, because 21111034523 - 2⁸ = 21111034267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21111034543) 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 3 ways as a sum of consecutive naturals, for example, 502808 + ... + 543173.

It is an arithmetic number, because the mean of its divisors is an integer number (5278025172).

Almost surely, 2^21111034523 is an apocalyptic number.

21111034523 is a deficient number, since it is larger than the sum of its proper divisors (1066165).

21111034523 is a wasteful number, since it uses less digits than its factorization.

21111034523 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1066164.

The product of its (nonzero) digits is 720, while the sum is 23.

Adding to 21111034523 its reverse (32543011112), we get a palindrome (53654045635).

The spelling of 21111034523 in words is "twenty-one billion, one hundred eleven million, thirty-four thousand, five hundred twenty-three".