21397838128 has 10 divisors (see below), whose sum is σ = 41458311404. Its totient is φ = 10698919056.

The previous prime is 21397838053. The next prime is 21397838129. The reversal of 21397838128 is 82183879312.

It is not an unprimeable number, because it can be changed into a prime (21397838129) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 668682426 + ... + 668682457.

Almost surely, 2^21397838128 is an apocalyptic number.

It is an amenable number.

21397838128 is a deficient number, since it is larger than the sum of its proper divisors (20060473276).

21397838128 is a wasteful number, since it uses less digits than its factorization.

21397838128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1337364891 (or 1337364885 counting only the distinct ones).

The product of its digits is 1161216, while the sum is 52.

The spelling of 21397838128 in words is "twenty-one billion, three hundred ninety-seven million, eight hundred thirty-eight thousand, one hundred twenty-eight".