21944503638 has 40 divisors (see below), whose sum is σ = 50867538480. Its totient is φ = 7062597360.

The previous prime is 21944503591. The next prime is 21944503643. The reversal of 21944503638 is 83630544912.

21944503638 is a `hidden beast` number, since 2 + 1 + 9 + 4 + 4 + 5 + 0 + 3 + 638 = 666.

It is a super-2 number, since 2×21944503638² (a number of 21 digits) contains 22 as substring.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21944503593 and 21944503602.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 2330818 + ... + 2340213.

It is an arithmetic number, because the mean of its divisors is an integer number (1271688462).

Almost surely, 2^21944503638 is an apocalyptic number.

21944503638 is an abundant number, since it is smaller than the sum of its proper divisors (28923034842).

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

21944503638 is a wasteful number, since it uses less digits than its factorization.

21944503638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4671074 (or 4671065 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 45.

The spelling of 21944503638 in words is "twenty-one billion, nine hundred forty-four million, five hundred three thousand, six hundred thirty-eight".