211639968 has 72 divisors (see below), whose sum is σ = 604667700. Its totient is φ = 70216704.

The previous prime is 211639949. The next prime is 211639969. The reversal of 211639968 is 869936112.

It is a happy number.

211639968 is a `hidden beast` number, since 2 + 1 + 1 + 639 + 9 + 6 + 8 = 666.

211639968 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 194100624 + 17539344 = 13932^2 + 4188^2 .

It is a tau number, because it is divible by the number of its divisors (72).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (211639969) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 64348 + ... + 67556.

Almost surely, 2^211639968 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 211639968, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (302333850).

211639968 is an abundant number, since it is smaller than the sum of its proper divisors (393027732).

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

211639968 is a wasteful number, since it uses less digits than its factorization.

211639968 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3454 (or 3443 counting only the distinct ones).

The product of its digits is 139968, while the sum is 45.

The square root of 211639968 is about 14547.8509753159. The cubic root of 211639968 is about 595.9354613839.

The spelling of 211639968 in words is "two hundred eleven million, six hundred thirty-nine thousand, nine hundred sixty-eight".