21953800 has 96 divisors (see below), whose sum is σ = 59058720. Its totient is φ = 7500800.

The previous prime is 21953791. The next prime is 21953803. The reversal of 21953800 is 835912.

It is not an unprimeable number, because it can be changed into a prime (21953803) 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 23 ways as a sum of consecutive naturals, for example, 37107 + ... + 37693.

It is an arithmetic number, because the mean of its divisors is an integer number (615195).

Almost surely, 2^21953800 is an apocalyptic number.

21953800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21953800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29529360).

21953800 is an abundant number, since it is smaller than the sum of its proper divisors (37104920).

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

21953800 is a wasteful number, since it uses less digits than its factorization.

21953800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 631 (or 622 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 21953800 is about 4685.4882349655. The cubic root of 21953800 is about 280.0076528521.

It can be divided in two parts, 2195 and 3800, that added together give a palindrome (5995).

The spelling of 21953800 in words is "twenty-one million, nine hundred fifty-three thousand, eight hundred".