210012021 has 24 divisors (see below), whose sum is σ = 318922240. Its totient is φ = 138078432.

The previous prime is 210012013. The next prime is 210012029. The reversal of 210012021 is 120210012.

It is an interprime number because it is at equal distance from previous prime (210012013) and next prime (210012029).

It is not a de Polignac number, because 210012021 - 2³ = 210012013 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 = 210011994 and 210012012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (210012029) 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 23 ways as a sum of consecutive naturals, for example, 11820 + ... + 23658.

Almost surely, 2^210012021 is an apocalyptic number.

It is an amenable number.

210012021 is a deficient number, since it is larger than the sum of its proper divisors (108910219).

210012021 is an equidigital number, since it uses as much as digits as its factorization.

210012021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11927 (or 11915 counting only the distinct ones).

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

The square root of 210012021 is about 14491.7915041585. The cubic root of 210012021 is about 594.4035366291.

Adding to 210012021 its reverse (120210012), we get a palindrome (330222033).

The spelling of 210012021 in words is "two hundred ten million, twelve thousand, twenty-one".