21448981644 has 24 divisors (see below), whose sum is σ = 50052571968. Its totient is φ = 7148953680.

The previous prime is 21448981639. The next prime is 21448981667. The reversal of 21448981644 is 44618984412.

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, 46279 + ... + 212225.

It is an arithmetic number, because the mean of its divisors is an integer number (2085523832).

Almost surely, 2^21448981644 is an apocalyptic number.

It is an amenable number.

21448981644 is an abundant number, since it is smaller than the sum of its proper divisors (28603590324).

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

21448981644 is a wasteful number, since it uses less digits than its factorization.

21448981644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176725 (or 176723 counting only the distinct ones).

The product of its digits is 1769472, while the sum is 51.

The spelling of 21448981644 in words is "twenty-one billion, four hundred forty-eight million, nine hundred eighty-one thousand, six hundred forty-four".