21445700 has 18 divisors (see below), whose sum is σ = 46537386. Its totient is φ = 8578240.

The previous prime is 21445673. The next prime is 21445717. The reversal of 21445700 is 754412.

It can be written as a sum of positive squares in 3 ways, for example, as 5827396 + 15618304 = 2414^2 + 3952^2 .

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, 107129 + ... + 107328.

Almost surely, 2^21445700 is an apocalyptic number.

21445700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21445700 is an abundant number, since it is smaller than the sum of its proper divisors (25091686).

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

21445700 is a wasteful number, since it uses less digits than its factorization.

21445700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214471 (or 214464 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 21445700 is about 4630.9502264654. The cubic root of 21445700 is about 277.8305991402.

The spelling of 21445700 in words is "twenty-one million, four hundred forty-five thousand, seven hundred".