21055700 has 18 divisors (see below), whose sum is σ = 45691086. Its totient is φ = 8422240.

The previous prime is 21055691. The next prime is 21055703. The reversal of 21055700 is 755012.

It can be written as a sum of positive squares in 3 ways, for example, as 1993744 + 19061956 = 1412^2 + 4366^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21055703) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 105179 + ... + 105378.

Almost surely, 2^21055700 is an apocalyptic number.

21055700 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21055700 is an abundant number, since it is smaller than the sum of its proper divisors (24635386).

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

21055700 is a wasteful number, since it uses less digits than its factorization.

21055700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 210571 (or 210564 counting only the distinct ones).

The product of its (nonzero) digits is 350, while the sum is 20.

The square root of 21055700 is about 4588.6490386605. The cubic root of 21055700 is about 276.1361262268.

The spelling of 21055700 in words is "twenty-one million, fifty-five thousand, seven hundred".