21012231011 has 4 divisors (see below), whose sum is σ = 21198180072. Its totient is φ = 20826281952.

The previous prime is 21012230989. The next prime is 21012231041. The reversal of 21012231011 is 11013221012.

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

It is a cyclic number.

It is not a de Polignac number, because 21012231011 - 2¹⁸ = 21011968867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21012231041) 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, 92974361 + ... + 92974586.

It is an arithmetic number, because the mean of its divisors is an integer number (5299545018).

Almost surely, 2^21012231011 is an apocalyptic number.

21012231011 is a deficient number, since it is larger than the sum of its proper divisors (185949061).

21012231011 is a wasteful number, since it uses less digits than its factorization.

21012231011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185949060.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21012231011 its reverse (11013221012), we get a palindrome (32025452023).

Subtracting from 21012231011 its reverse (11013221012), we obtain a palindrome (9999009999).

The spelling of 21012231011 in words is "twenty-one billion, twelve million, two hundred thirty-one thousand, eleven".