210020121 has 20 divisors (see below), whose sum is σ = 315678352. Its totient is φ = 139145688.

The previous prime is 210020101. The next prime is 210020137. The reversal of 210020121 is 121020012.

It is not a de Polignac number, because 210020121 - 2⁹ = 210019609 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 not an unprimeable number, because it can be changed into a prime (210020101) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 5250 + ... + 21156.

Almost surely, 2^210020121 is an apocalyptic number.

It is an amenable number.

210020121 is a deficient number, since it is larger than the sum of its proper divisors (105658231).

210020121 is a wasteful number, since it uses less digits than its factorization.

210020121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16082 (or 16073 counting only the distinct ones).

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

The square root of 210020121 is about 14492.0709700167. The cubic root of 210020121 is about 594.4111784246.

Adding to 210020121 its reverse (121020012), we get a palindrome (331040133).

The spelling of 210020121 in words is "two hundred ten million, twenty thousand, one hundred twenty-one".