201210021 has 8 divisors (see below), whose sum is σ = 298088960. Its totient is φ = 134139996.

The previous prime is 201210013. The next prime is 201210071. The reversal of 201210021 is 120012102.

It is not a de Polignac number, because 201210021 - 2³ = 201210013 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 201209985 and 201210012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (201210071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3726085 + ... + 3726138.

It is an arithmetic number, because the mean of its divisors is an integer number (37261120).

Almost surely, 2^201210021 is an apocalyptic number.

It is an amenable number.

201210021 is a deficient number, since it is larger than the sum of its proper divisors (96878939).

201210021 is an equidigital number, since it uses as much as digits as its factorization.

201210021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7452232 (or 7452226 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

The square root of 201210021 is about 14184.8518145238. The cubic root of 201210021 is about 585.9805514479.

Adding to 201210021 its reverse (120012102), we get a palindrome (321222123).

The spelling of 201210021 in words is "two hundred one million, two hundred ten thousand, twenty-one".