21440173648 has 40 divisors (see below), whose sum is σ = 43775233920. Its totient is φ = 10144592640.

The previous prime is 21440173621. The next prime is 21440173691. The reversal of 21440173648 is 84637104412.

It is a self number, because there is not a number n which added to its sum of digits gives 21440173648.

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, 238236 + ... + 315652.

It is an arithmetic number, because the mean of its divisors is an integer number (1094380848).

Almost surely, 2^21440173648 is an apocalyptic number.

It is an amenable number.

21440173648 is an abundant number, since it is smaller than the sum of its proper divisors (22335060272).

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

21440173648 is a wasteful number, since it uses less digits than its factorization.

21440173648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78355 (or 78349 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 40.

The spelling of 21440173648 in words is "twenty-one billion, four hundred forty million, one hundred seventy-three thousand, six hundred forty-eight".