21101202221 has 12 divisors (see below), whose sum is σ = 23230724832. Its totient is φ = 19152441000.

The previous prime is 21101202217. The next prime is 21101202251. The reversal of 21101202221 is 12220210112.

It is not a de Polignac number, because 21101202221 - 2² = 21101202217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21101202196 and 21101202205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101202251) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 61835 + ... + 214536.

It is an arithmetic number, because the mean of its divisors is an integer number (1935893736).

Almost surely, 2^21101202221 is an apocalyptic number.

It is an amenable number.

21101202221 is a deficient number, since it is larger than the sum of its proper divisors (2129522611).

21101202221 is a wasteful number, since it uses less digits than its factorization.

21101202221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277024 (or 277013 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21101202221 its reverse (12220210112), we get a palindrome (33321412333).

It can be divided in two parts, 21101 and 202221, that added together give a palindrome (223322).

The spelling of 21101202221 in words is "twenty-one billion, one hundred one million, two hundred two thousand, two hundred twenty-one".