21112012221 has 16 divisors (see below), whose sum is σ = 28618733760. Its totient is φ = 13840110720.

The previous prime is 21112012217. The next prime is 21112012253. The reversal of 21112012221 is 12221021112.

It is not a de Polignac number, because 21112012221 - 2² = 21112012217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21112012221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112012211) 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, 746110 + ... + 773888.

It is an arithmetic number, because the mean of its divisors is an integer number (1788670860).

Almost surely, 2^21112012221 is an apocalyptic number.

It is an amenable number.

21112012221 is a deficient number, since it is larger than the sum of its proper divisors (7506721539).

21112012221 is a wasteful number, since it uses less digits than its factorization.

21112012221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31996.

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

Adding to 21112012221 its reverse (12221021112), we get a palindrome (33333033333).

The spelling of 21112012221 in words is "twenty-one billion, one hundred twelve million, twelve thousand, two hundred twenty-one".