21201010111 has 4 divisors (see below), whose sum is σ = 21202953192. Its totient is φ = 21199067032.

The previous prime is 21201010093. The next prime is 21201010183. The reversal of 21201010111 is 11101010212.

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 21201010111 - 2⁷ = 21201009983 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 (21201013111) 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, 955081 + ... + 977026.

It is an arithmetic number, because the mean of its divisors is an integer number (5300738298).

Almost surely, 2^21201010111 is an apocalyptic number.

21201010111 is a deficient number, since it is larger than the sum of its proper divisors (1943081).

21201010111 is a wasteful number, since it uses less digits than its factorization.

21201010111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1943080.

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21201010111 its reverse (11101010212), we get a palindrome (32302020323).

The spelling of 21201010111 in words is "twenty-one billion, two hundred one million, ten thousand, one hundred eleven".