211220128 has 48 divisors (see below), whose sum is σ = 486319680. Its totient is φ = 88413696.

The previous prime is 211220123. The next prime is 211220153. The reversal of 211220128 is 821022112.

211220128 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×211220128² = 89227884944672768, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (211220123) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1333 + ... + 20596.

It is an arithmetic number, because the mean of its divisors is an integer number (10131660).

Almost surely, 2^211220128 is an apocalyptic number.

211220128 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 211220128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (243159840).

211220128 is an abundant number, since it is smaller than the sum of its proper divisors (275099552).

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

211220128 is a wasteful number, since it uses less digits than its factorization.

211220128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21989 (or 21981 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

The square root of 211220128 is about 14533.4141893775. The cubic root of 211220128 is about 595.5411389380.

The spelling of 211220128 in words is "two hundred eleven million, two hundred twenty thousand, one hundred twenty-eight".