21021021212111 has 16 divisors (see below), whose sum is σ = 21154420494720. Its totient is φ = 20888027731200.

The previous prime is 21021021212053. The next prime is 21021021212131. The reversal of 21021021212111 is 11121212012012.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21021021212111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21021021212111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021021212131) 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, 393618011 + ... + 393671411.

It is an arithmetic number, because the mean of its divisors is an integer number (1322151280920).

Almost surely, 2^{21021021212111} is an apocalyptic number.

21021021212111 is a deficient number, since it is larger than the sum of its proper divisors (133399282609).

21021021212111 is a wasteful number, since it uses less digits than its factorization.

21021021212111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57154.

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21021021212111 its reverse (11121212012012), we get a palindrome (32142233224123).

The spelling of 21021021212111 in words is "twenty-one trillion, twenty-one billion, twenty-one million, two hundred twelve thousand, one hundred eleven".