21235210 has 32 divisors (see below), whose sum is σ = 42239232. Its totient is φ = 7645440.

The previous prime is 21235183. The next prime is 21235213. The reversal of 21235210 is 1253212.

It is not an unprimeable number, because it can be changed into a prime (21235213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1195 + ... + 6625.

It is an arithmetic number, because the mean of its divisors is an integer number (1319976).

Almost surely, 2^21235210 is an apocalyptic number.

21235210 is a deficient number, since it is larger than the sum of its proper divisors (21004022).

21235210 is a wasteful number, since it uses less digits than its factorization.

21235210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5478.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21235210 is about 4608.1677486828. The cubic root of 21235210 is about 276.9186378878.

Adding to 21235210 its reverse (1253212), we get a palindrome (22488422).

The spelling of 21235210 in words is "twenty-one million, two hundred thirty-five thousand, two hundred ten".