21443664438 has 40 divisors (see below), whose sum is σ = 54913937232. Its totient is φ = 6126760944.

The previous prime is 21443664421. The next prime is 21443664469. The reversal of 21443664438 is 83446634412.

21443664438 is a `hidden beast` number, since 2 + 144 + 3 + 66 + 443 + 8 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21443664393 and 21443664402.

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, 9453745 + ... + 9456012.

Almost surely, 2^21443664438 is an apocalyptic number.

21443664438 is an abundant number, since it is smaller than the sum of its proper divisors (33470272794).

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

21443664438 is a wasteful number, since it uses less digits than its factorization.

21443664438 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18909778 (or 18909769 counting only the distinct ones).

The product of its digits is 1327104, while the sum is 45.

The spelling of 21443664438 in words is "twenty-one billion, four hundred forty-three million, six hundred sixty-four thousand, four hundred thirty-eight".