21144208984 has 8 divisors (see below), whose sum is σ = 39645391860. Its totient is φ = 10572104488.

The previous prime is 21144208979. The next prime is 21144209039. The reversal of 21144208984 is 48980244112.

It is a tau number, because it is divible by the number of its divisors (8).

It is a self number, because there is not a number n which added to its sum of digits gives 21144208984.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1321513054 + ... + 1321513069.

Almost surely, 2^21144208984 is an apocalyptic number.

It is an amenable number.

21144208984 is a deficient number, since it is larger than the sum of its proper divisors (18501182876).

21144208984 is a wasteful number, since it uses less digits than its factorization.

21144208984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2643026129 (or 2643026125 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 43.

The spelling of 21144208984 in words is "twenty-one billion, one hundred forty-four million, two hundred eight thousand, nine hundred eighty-four".