21101210 has 32 divisors (see below), whose sum is σ = 43061760. Its totient is φ = 7380288.

The previous prime is 21101209. The next prime is 21101219. The reversal of 21101210 is 1210112.

It is a super-2 number, since 2×21101210² = 890522126928200, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21101219) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 1802 + ... + 6741.

It is an arithmetic number, because the mean of its divisors is an integer number (1345680).

Almost surely, 2^21101210 is an apocalyptic number.

21101210 is an abundant number, since it is smaller than the sum of its proper divisors (21960550).

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

21101210 is a wasteful number, since it uses less digits than its factorization.

21101210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8582.

The product of its (nonzero) digits is 4, while the sum is 8.

The square root of 21101210 is about 4593.6053378583. The cubic root of 21101210 is about 276.3349308552.

Adding to 21101210 its reverse (1210112), we get a palindrome (22311322).

The spelling of 21101210 in words is "twenty-one million, one hundred one thousand, two hundred ten".