21121011988 has 12 divisors (see below), whose sum is σ = 36966398112. Its totient is φ = 10559183960.

The previous prime is 21121011959. The next prime is 21121012021. The reversal of 21121011988 is 88911012112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 294118 + ... + 358813.

It is an arithmetic number, because the mean of its divisors is an integer number (3080533176).

Almost surely, 2^21121011988 is an apocalyptic number.

It is an amenable number.

21121011988 is a deficient number, since it is larger than the sum of its proper divisors (15845386124).

21121011988 is a wasteful number, since it uses less digits than its factorization.

21121011988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 661022 (or 661020 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 34.

The spelling of 21121011988 in words is "twenty-one billion, one hundred twenty-one million, eleven thousand, nine hundred eighty-eight".