211166220 has 72 divisors (see below), whose sum is σ = 618183216. Its totient is φ = 53854592.

The previous prime is 211166213. The next prime is 211166233. The reversal of 211166220 is 22661112.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 28414 + ... + 35066.

It is an arithmetic number, because the mean of its divisors is an integer number (8585878).

Almost surely, 2^211166220 is an apocalyptic number.

211166220 is a gapful number since it is divisible by the number (20) 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 211166220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (309091608).

211166220 is an abundant number, since it is smaller than the sum of its proper divisors (407016996).

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

211166220 is a wasteful number, since it uses less digits than its factorization.

211166220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6711 (or 6686 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 211166220 is about 14531.5594483180. The cubic root of 211166220 is about 595.4904695824.

The spelling of 211166220 in words is "two hundred eleven million, one hundred sixty-six thousand, two hundred twenty".