20999800 has 24 divisors (see below), whose sum is σ = 48825000. Its totient is φ = 8399840.

The previous prime is 20999791. The next prime is 20999843. The reversal of 20999800 is 899902.

It is a self number, because there is not a number n which added to its sum of digits gives 20999800.

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 5 ways as a sum of consecutive naturals, for example, 52300 + ... + 52699.

It is an arithmetic number, because the mean of its divisors is an integer number (2034375).

Almost surely, 2^20999800 is an apocalyptic number.

20999800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20999800 is an abundant number, since it is smaller than the sum of its proper divisors (27825200).

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

20999800 is a wasteful number, since it uses less digits than its factorization.

20999800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105015 (or 105006 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 20999800 is about 4582.5538731149. The cubic root of 20999800 is about 275.8915417864.

The spelling of 20999800 in words is "twenty million, nine hundred ninety-nine thousand, eight hundred".