21055210 has 24 divisors (see below), whose sum is σ = 41660388. Its totient is φ = 7656000.

The previous prime is 21055207. The next prime is 21055213. The reversal of 21055210 is 1255012.

It is an interprime number because it is at equal distance from previous prime (21055207) and next prime (21055213).

It can be written as a sum of positive squares in 2 ways, for example, as 21040569 + 14641 = 4587^2 + 121^2 .

It is not an unprimeable number, because it can be changed into a prime (21055213) 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 11 ways as a sum of consecutive naturals, for example, 7491 + ... + 9910.

Almost surely, 2^21055210 is an apocalyptic number.

21055210 is a deficient number, since it is larger than the sum of its proper divisors (20605178).

21055210 is a wasteful number, since it uses less digits than its factorization.

21055210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17430 (or 17419 counting only the distinct ones).

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 21055210 is about 4588.5956457287. The cubic root of 21055210 is about 276.1339841662.

The spelling of 21055210 in words is "twenty-one million, fifty-five thousand, two hundred ten".