21221213344 has 24 divisors (see below), whose sum is σ = 41782632948. Its totient is φ = 10609751040.

The previous prime is 21221213249. The next prime is 21221213347. The reversal of 21221213344 is 44331212212.

It can be written as a sum of positive squares in 2 ways, for example, as 20281177744 + 940035600 = 142412^2 + 30660^2 .

It is not an unprimeable number, because it can be changed into a prime (21221213347) 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, 608344 + ... + 642280.

Almost surely, 2^21221213344 is an apocalyptic number.

It is an amenable number.

21221213344 is a deficient number, since it is larger than the sum of its proper divisors (20561419604).

21221213344 is a wasteful number, since it uses less digits than its factorization.

21221213344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53488 (or 53480 counting only the distinct ones).

The product of its digits is 2304, while the sum is 25.

Adding to 21221213344 its reverse (44331212212), we get a palindrome (65552425556).

The spelling of 21221213344 in words is "twenty-one billion, two hundred twenty-one million, two hundred thirteen thousand, three hundred forty-four".