21000088 has 8 divisors (see below), whose sum is σ = 39375180. Its totient is φ = 10500040.

The previous prime is 21000059. The next prime is 21000097. The reversal of 21000088 is 88000012.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (19) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1312498 + ... + 1312513.

Almost surely, 2^21000088 is an apocalyptic number.

It is an amenable number.

21000088 is a deficient number, since it is larger than the sum of its proper divisors (18375092).

21000088 is a wasteful number, since it uses less digits than its factorization.

21000088 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2625017 (or 2625013 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 21000088 is about 4582.5852965330. The cubic root of 21000088 is about 275.8928030111.

The spelling of 21000088 in words is "twenty-one million, eighty-eight", and thus it is an aban number and an uban number.