21010221111 has 24 divisors (see below), whose sum is σ = 30806279280. Its totient is φ = 12727496320.

The previous prime is 21010221073. The next prime is 21010221121. The reversal of 21010221111 is 11112201012.

It is not a de Polignac number, because 21010221111 - 2⁷ = 21010220983 is a prime.

It is a super-4 number, since 4×21010221111⁴ (a number of 42 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010221121) 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, 834475 + ... + 859283.

It is an arithmetic number, because the mean of its divisors is an integer number (1283594970).

Almost surely, 2^21010221111 is an apocalyptic number.

21010221111 is a deficient number, since it is larger than the sum of its proper divisors (9796058169).

21010221111 is a wasteful number, since it uses less digits than its factorization.

21010221111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27167 (or 27156 counting only the distinct ones).

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

Adding to 21010221111 its reverse (11112201012), we get a palindrome (32122422123).

The spelling of 21010221111 in words is "twenty-one billion, ten million, two hundred twenty-one thousand, one hundred eleven".