21438764488 has 48 divisors (see below), whose sum is σ = 41588329500. Its totient is φ = 10360586880.

The previous prime is 21438764387. The next prime is 21438764491. The reversal of 21438764488 is 88446783412.

It can be written as a sum of positive squares in 2 ways, for example, as 21391402564 + 47361924 = 146258^2 + 6882^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 9447418 + ... + 9449686.

Almost surely, 2^21438764488 is an apocalyptic number.

It is an amenable number.

21438764488 is a deficient number, since it is larger than the sum of its proper divisors (20149565012).

21438764488 is a wasteful number, since it uses less digits than its factorization.

21438764488 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3566 (or 3531 counting only the distinct ones).

The product of its digits is 8257536, while the sum is 55.

The spelling of 21438764488 in words is "twenty-one billion, four hundred thirty-eight million, seven hundred sixty-four thousand, four hundred eighty-eight".