21111020023 has 4 divisors (see below), whose sum is σ = 22222126360. Its totient is φ = 19999913688.

The previous prime is 21111020009. The next prime is 21111020039. The reversal of 21111020023 is 32002011112.

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 21111020023 - 2⁵ = 21111019991 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21111019985 and 21111020012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111020083) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 555553140 + ... + 555553177.

It is an arithmetic number, because the mean of its divisors is an integer number (5555531590).

Almost surely, 2^21111020023 is an apocalyptic number.

21111020023 is a deficient number, since it is larger than the sum of its proper divisors (1111106337).

21111020023 is a wasteful number, since it uses less digits than its factorization.

21111020023 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111106336.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21111020023 its reverse (32002011112), we get a palindrome (53113031135).

The spelling of 21111020023 in words is "twenty-one billion, one hundred eleven million, twenty thousand, twenty-three".