21689800 has 48 divisors (see below), whose sum is σ = 55018800. Its totient is φ = 7886400.

The previous prime is 21689797. The next prime is 21689803. The reversal of 21689800 is 898612.

It is an interprime number because it is at equal distance from previous prime (21689797) and next prime (21689803).

It is not an unprimeable number, because it can be changed into a prime (21689803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2730 + ... + 7129.

It is an arithmetic number, because the mean of its divisors is an integer number (1146225).

Almost surely, 2^21689800 is an apocalyptic number.

21689800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21689800 is an abundant number, since it is smaller than the sum of its proper divisors (33329000).

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

21689800 is a wasteful number, since it uses less digits than its factorization.

21689800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9886 (or 9877 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 21689800 is about 4657.2309369410. The cubic root of 21689800 is about 278.8807359287.

The spelling of 21689800 in words is "twenty-one million, six hundred eighty-nine thousand, eight hundred".