21001210 has 8 divisors (see below), whose sum is σ = 37802196. Its totient is φ = 8400480.

The previous prime is 21001187. The next prime is 21001247. The reversal of 21001210 is 1210012.

It can be written as a sum of positive squares in 2 ways, for example, as 20277009 + 724201 = 4503^2 + 851^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 21001193 and 21001202.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1050051 + ... + 1050070.

Almost surely, 2^21001210 is an apocalyptic number.

21001210 is a deficient number, since it is larger than the sum of its proper divisors (16800986).

21001210 is a wasteful number, since it uses less digits than its factorization.

21001210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2100128.

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

The square root of 21001210 is about 4582.7077148777. The cubic root of 21001210 is about 275.8977164225.

Adding to 21001210 its reverse (1210012), we get a palindrome (22211222).

The spelling of 21001210 in words is "twenty-one million, one thousand, two hundred ten".