210121128 has 112 divisors (see below), whose sum is σ = 675211680. Its totient is φ = 60022944.

The previous prime is 210121103. The next prime is 210121151. The reversal of 210121128 is 821121012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 210121128.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 38251 + ... + 43397.

Almost surely, 2^210121128 is an apocalyptic number.

210121128 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 210121128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (337605840).

210121128 is an abundant number, since it is smaller than the sum of its proper divisors (465090552).

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

210121128 is an equidigital number, since it uses as much as digits as its factorization.

210121128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5178 (or 5159 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 210121128 is about 14495.5554567598. Note that the first 3 decimals coincide. The cubic root of 210121128 is about 594.5064551168.

The spelling of 210121128 in words is "two hundred ten million, one hundred twenty-one thousand, one hundred twenty-eight".