21000798 has 48 divisors (see below), whose sum is σ = 56006496. Its totient is φ = 5538240.

The previous prime is 21000779. The next prime is 21000803. The reversal of 21000798 is 89700012.

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 in 23 ways as a sum of consecutive naturals, for example, 4773 + ... + 8048.

It is an arithmetic number, because the mean of its divisors is an integer number (1166802).

Almost surely, 2^21000798 is an apocalyptic number.

21000798 is an abundant number, since it is smaller than the sum of its proper divisors (35005698).

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

21000798 is a wasteful number, since it uses less digits than its factorization.

21000798 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12849 (or 12846 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 21000798 is about 4582.6627630669. The cubic root of 21000798 is about 275.8959122311.

The spelling of 21000798 in words is "twenty-one million, seven hundred ninety-eight", and thus it is an aban number.