21957800 has 24 divisors (see below), whose sum is σ = 51052350. Its totient is φ = 8783040.

The previous prime is 21957799. The next prime is 21957809. The reversal of 21957800 is 875912.

It can be written as a sum of positive squares in 3 ways, for example, as 16859236 + 5098564 = 4106^2 + 2258^2 .

It is not an unprimeable number, because it can be changed into a prime (21957809) by changing a digit.

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, 54695 + ... + 55094.

Almost surely, 2^21957800 is an apocalyptic number.

21957800 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21957800 is an abundant number, since it is smaller than the sum of its proper divisors (29094550).

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

21957800 is a wasteful number, since it uses less digits than its factorization.

21957800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 109805 (or 109796 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 21957800 is about 4685.9150653848. The cubic root of 21957800 is about 280.0246576924.

The spelling of 21957800 in words is "twenty-one million, nine hundred fifty-seven thousand, eight hundred".