21001107988 has 12 divisors (see below), whose sum is σ = 42002216032. Its totient is φ = 9000474840.

The previous prime is 21001107971. The next prime is 21001107989. The reversal of 21001107988 is 88970110012.

21001107988 is an admirable number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001107989) 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 in 3 ways as a sum of consecutive naturals, for example, 375019758 + ... + 375019813.

Almost surely, 2^21001107988 is an apocalyptic number.

21001107988 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21001107988 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21001107988 is a wasteful number, since it uses less digits than its factorization.

21001107988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 750039582 (or 750039580 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 37.

The spelling of 21001107988 in words is "twenty-one billion, one million, one hundred seven thousand, nine hundred eighty-eight".