21221224404 has 12 divisors (see below), whose sum is σ = 49516190304. Its totient is φ = 7073741464.

The previous prime is 21221224357. The next prime is 21221224463. The reversal of 21221224404 is 40442212212.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 884217672 + ... + 884217695.

It is an arithmetic number, because the mean of its divisors is an integer number (4126349192).

Almost surely, 2^21221224404 is an apocalyptic number.

It is an amenable number.

21221224404 is an abundant number, since it is smaller than the sum of its proper divisors (28294965900).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21221224404 is a wasteful number, since it uses less digits than its factorization.

21221224404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1768435374 (or 1768435372 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 24.

Adding to 21221224404 its reverse (40442212212), we get a palindrome (61663436616).

The spelling of 21221224404 in words is "twenty-one billion, two hundred twenty-one million, two hundred twenty-four thousand, four hundred four".