21111021229 has 4 divisors (see below), whose sum is σ = 21131458876. Its totient is φ = 21090583584.

The previous prime is 21111021227. The next prime is 21111021251. The reversal of 21111021229 is 92212011112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 13537322500 + 7573698729 = 116350^2 + 87027^2 .

It is a cyclic number.

It is not a de Polignac number, because 21111021229 - 2¹ = 21111021227 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111021227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10217274 + ... + 10219339.

It is an arithmetic number, because the mean of its divisors is an integer number (5282864719).

Almost surely, 2^21111021229 is an apocalyptic number.

It is an amenable number.

21111021229 is a deficient number, since it is larger than the sum of its proper divisors (20437647).

21111021229 is a wasteful number, since it uses less digits than its factorization.

21111021229 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20437646.

The product of its (nonzero) digits is 144, while the sum is 22.

The spelling of 21111021229 in words is "twenty-one billion, one hundred eleven million, twenty-one thousand, two hundred twenty-nine".