21111120021 has 16 divisors (see below), whose sum is σ = 28324486080. Its totient is φ = 13986188160.

The previous prime is 21111120011. The next prime is 21111120029. The reversal of 21111120021 is 12002111112.

It is not a de Polignac number, because 21111120021 - 2⁷ = 21111119893 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21111119979 and 21111120006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111120029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 280870 + ... + 348008.

It is an arithmetic number, because the mean of its divisors is an integer number (1770280380).

Almost surely, 2^21111120021 is an apocalyptic number.

It is an amenable number.

21111120021 is a deficient number, since it is larger than the sum of its proper divisors (7213366059).

21111120021 is a wasteful number, since it uses less digits than its factorization.

21111120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67796.

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21111120021 its reverse (12002111112), we get a palindrome (33113231133).

It can be divided in two parts, 211111 and 20021, that added together give a palindrome (231132).

The spelling of 21111120021 in words is "twenty-one billion, one hundred eleven million, one hundred twenty thousand, twenty-one".