21421440244 has 24 divisors (see below), whose sum is σ = 37886966208. Its totient is φ = 10596788160.

The previous prime is 21421440239. The next prime is 21421440269. The reversal of 21421440244 is 44204412412.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 425664 + ... + 473320.

It is an arithmetic number, because the mean of its divisors is an integer number (1578623592).

Almost surely, 2^21421440244 is an apocalyptic number.

It is an amenable number.

21421440244 is a deficient number, since it is larger than the sum of its proper divisors (16465525964).

21421440244 is a wasteful number, since it uses less digits than its factorization.

21421440244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48855 (or 48853 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 28.

Adding to 21421440244 its reverse (44204412412), we get a palindrome (65625852656).

The spelling of 21421440244 in words is "twenty-one billion, four hundred twenty-one million, four hundred forty thousand, two hundred forty-four".