21978061444 has 96 divisors (see below), whose sum is σ = 43500441600. Its totient is φ = 9671114880.

The previous prime is 21978061409. The next prime is 21978061451. The reversal of 21978061444 is 44416087912.

It is a junction number, because it is equal to n+sod(n) for n = 21978061394 and 21978061403.

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 31 ways as a sum of consecutive naturals, for example, 5975334 + ... + 5979010.

It is an arithmetic number, because the mean of its divisors is an integer number (453129600).

Almost surely, 2^21978061444 is an apocalyptic number.

It is an amenable number.

21978061444 is a deficient number, since it is larger than the sum of its proper divisors (21522380156).

21978061444 is a wasteful number, since it uses less digits than its factorization.

21978061444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3833 (or 3831 counting only the distinct ones).

The product of its (nonzero) digits is 387072, while the sum is 46.

The spelling of 21978061444 in words is "twenty-one billion, nine hundred seventy-eight million, sixty-one thousand, four hundred forty-four".