211331220 has 96 divisors (see below), whose sum is σ = 610315776. Its totient is φ = 54604800.

The previous prime is 211331203. The next prime is 211331227. The reversal of 211331220 is 22133112.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 211331220.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (211331227) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 666502 + ... + 666818.

It is an arithmetic number, because the mean of its divisors is an integer number (6357456).

Almost surely, 2^211331220 is an apocalyptic number.

211331220 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 211331220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (305157888).

211331220 is an abundant number, since it is smaller than the sum of its proper divisors (398984556).

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

211331220 is a wasteful number, since it uses less digits than its factorization.

211331220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 641 (or 639 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 211331220 is about 14537.2356381810. The cubic root of 211331220 is about 595.6455296531.

Adding to 211331220 its reverse (22133112), we get a palindrome (233464332).

It can be divided in two parts, 2113 and 31220, that added together give a palindrome (33333).

The spelling of 211331220 in words is "two hundred eleven million, three hundred thirty-one thousand, two hundred twenty".