21388543428 has 48 divisors (see below), whose sum is σ = 60038021120. Its totient is φ = 5789379744.

The previous prime is 21388543411. The next prime is 21388543459. The reversal of 21388543428 is 82434588312.

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 15 ways as a sum of consecutive naturals, for example, 6699076 + ... + 6702267.

Almost surely, 2^21388543428 is an apocalyptic number.

21388543428 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21388543428 is an abundant number, since it is smaller than the sum of its proper divisors (38649477692).

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

21388543428 is a wasteful number, since it uses less digits than its factorization.

21388543428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13401376 (or 13401374 counting only the distinct ones).

The product of its digits is 1474560, while the sum is 48.

The spelling of 21388543428 in words is "twenty-one billion, three hundred eighty-eight million, five hundred forty-three thousand, four hundred twenty-eight".