21020212121111 has 24 divisors (see below), whose sum is σ = 24594430666320. Its totient is φ = 17912445812352.

The previous prime is 21020212121089. The next prime is 21020212121147. The reversal of 21020212121111 is 11112121202012.

It is not a de Polignac number, because 21020212121111 - 2¹⁸ = 21020211858967 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 21020212121111.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020212121911) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 349044275 + ... + 349104491.

It is an arithmetic number, because the mean of its divisors is an integer number (1024767944430).

Almost surely, 2^{21020212121111} is an apocalyptic number.

21020212121111 is a deficient number, since it is larger than the sum of its proper divisors (3574218545209).

21020212121111 is a wasteful number, since it uses less digits than its factorization.

21020212121111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 101583 (or 101576 counting only the distinct ones).

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

Adding to 21020212121111 its reverse (11112121202012), we get a palindrome (32132333323123).

The spelling of 21020212121111 in words is "twenty-one trillion, twenty billion, two hundred twelve million, one hundred twenty-one thousand, one hundred eleven".