21993549378 has 16 divisors (see below), whose sum is σ = 44033266656. Its totient is φ = 7323488480.

The previous prime is 21993549317. The next prime is 21993549401. The reversal of 21993549378 is 87394539912.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1917468 + ... + 1928903.

It is an arithmetic number, because the mean of its divisors is an integer number (2752079166).

Almost surely, 2^21993549378 is an apocalyptic number.

21993549378 is an abundant number, since it is smaller than the sum of its proper divisors (22039717278).

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

21993549378 is a wasteful number, since it uses less digits than its factorization.

21993549378 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3847329.

The product of its digits is 14696640, while the sum is 60.

The spelling of 21993549378 in words is "twenty-one billion, nine hundred ninety-three million, five hundred forty-nine thousand, three hundred seventy-eight".