21006888 has 48 divisors (see below), whose sum is σ = 61094880. Its totient is φ = 6001632.

The previous prime is 21006877. The next prime is 21006893. The reversal of 21006888 is 88860012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7756 + ... + 10107.

It is an arithmetic number, because the mean of its divisors is an integer number (1272810).

Almost surely, 2^21006888 is an apocalyptic number.

21006888 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21006888 is an abundant number, since it is smaller than the sum of its proper divisors (40087992).

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

21006888 is a wasteful number, since it uses less digits than its factorization.

21006888 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17886 (or 17875 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 33.

The square root of 21006888 is about 4583.3271757534. The cubic root of 21006888 is about 275.9225785784.

The spelling of 21006888 in words is "twenty-one million, six thousand, eight hundred eighty-eight".