21055570 has 8 divisors (see below), whose sum is σ = 37900044. Its totient is φ = 8422224.

The previous prime is 21055561. The next prime is 21055579. The reversal of 21055570 is 7555012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21055561) and next prime (21055579).

It can be written as a sum of positive squares in 2 ways, for example, as 19882681 + 1172889 = 4459^2 + 1083^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (21055579) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1052769 + ... + 1052788.

Almost surely, 2^21055570 is an apocalyptic number.

21055570 is a deficient number, since it is larger than the sum of its proper divisors (16844474).

21055570 is a wasteful number, since it uses less digits than its factorization.

21055570 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2105564.

The product of its (nonzero) digits is 1750, while the sum is 25.

The square root of 21055570 is about 4588.6348732493. The cubic root of 21055570 is about 276.1355579282.

The spelling of 21055570 in words is "twenty-one million, fifty-five thousand, five hundred seventy".