21010210 has 32 divisors (see below), whose sum is σ = 42139440. Its totient is φ = 7488768.

The previous prime is 21010193. The next prime is 21010217. The reversal of 21010210 is 1201012.

It can be written as a sum of positive squares in 8 ways, for example, as 1216609 + 19793601 = 1103^2 + 4449^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21010193 and 21010202.

It is not an unprimeable number, because it can be changed into a prime (21010217) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 984 + ... + 6556.

Almost surely, 2^21010210 is an apocalyptic number.

21010210 is an abundant number, since it is smaller than the sum of its proper divisors (21129230).

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

21010210 is a wasteful number, since it uses less digits than its factorization.

21010210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5622.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 21010210 is about 4583.6895619141. The cubic root of 21010210 is about 275.9371224825.

Adding to 21010210 its reverse (1201012), we get a palindrome (22211222).

The spelling of 21010210 in words is "twenty-one million, ten thousand, two hundred ten".