21201112221 has 16 divisors (see below), whose sum is σ = 29381951424. Its totient is φ = 13586379264.

The previous prime is 21201112217. The next prime is 21201112241. The reversal of 21201112221 is 12221110212.

It is not a de Polignac number, because 21201112221 - 2² = 21201112217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21201112221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201112241) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1141396 + ... + 1159821.

It is an arithmetic number, because the mean of its divisors is an integer number (1836371964).

Almost surely, 2^21201112221 is an apocalyptic number.

It is an amenable number.

21201112221 is a deficient number, since it is larger than the sum of its proper divisors (8180839203).

21201112221 is a wasteful number, since it uses less digits than its factorization.

21201112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2301340.

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21201112221 its reverse (12221110212), we get a palindrome (33422222433).

The spelling of 21201112221 in words is "twenty-one billion, two hundred one million, one hundred twelve thousand, two hundred twenty-one".