21214022221 has 12 divisors (see below), whose sum is σ = 24765372540. Its totient is φ = 18118726080.

The previous prime is 21214022201. The next prime is 21214022251. The reversal of 21214022221 is 12222041212.

It can be written as a sum of positive squares in 2 ways, for example, as 14622855625 + 6591166596 = 120925^2 + 81186^2 .

It is not a de Polignac number, because 21214022221 - 2¹⁵ = 21213989453 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 (21214022201) 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, 756586 + ... + 784123.

It is an arithmetic number, because the mean of its divisors is an integer number (2063781045).

Almost surely, 2^21214022221 is an apocalyptic number.

It is an amenable number.

21214022221 is a deficient number, since it is larger than the sum of its proper divisors (3551350319).

21214022221 is a wasteful number, since it uses less digits than its factorization.

21214022221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1541004 (or 1540997 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 19.

Adding to 21214022221 its reverse (12222041212), we get a palindrome (33436063433).

The spelling of 21214022221 in words is "twenty-one billion, two hundred fourteen million, twenty-two thousand, two hundred twenty-one".