21021002111 has 2 divisors, whose sum is σ = 21021002112. Its totient is φ = 21021002110.

The previous prime is 21021002087. The next prime is 21021002131. The reversal of 21021002111 is 11120012012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021002111 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21021002092 and 21021002101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021002131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510501055 + 10510501056.

It is an arithmetic number, because the mean of its divisors is an integer number (10510501056).

Almost surely, 2^21021002111 is an apocalyptic number.

21021002111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021002111 is an equidigital number, since it uses as much as digits as its factorization.

21021002111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 21021002111 its reverse (11120012012), we get a palindrome (32141014123).

Subtracting from 21021002111 its reverse (11120012012), we obtain a palindrome (9900990099).

The spelling of 21021002111 in words is "twenty-one billion, twenty-one million, two thousand, one hundred eleven".