211968081 has 18 divisors (see below), whose sum is σ = 331542198. Its totient is φ = 130440960.

The previous prime is 211968037. The next prime is 211968083. The reversal of 211968081 is 180869112.

It can be written as a sum of positive squares in 3 ways, for example, as 3600 + 211964481 = 60^2 + 14559^2 .

It is not a de Polignac number, because 211968081 - 2⁶ = 211968017 is a prime.

It is a super-2 number, since 2×211968081² = 89860934725645122, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (211968083) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 68160 + ... + 71201.

It is an arithmetic number, because the mean of its divisors is an integer number (18419011).

Almost surely, 2^211968081 is an apocalyptic number.

It is an amenable number.

211968081 is a deficient number, since it is larger than the sum of its proper divisors (119574117).

211968081 is a wasteful number, since it uses less digits than its factorization.

211968081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139393 (or 139377 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 36.

The square root of 211968081 is about 14559.1236343401. The cubic root of 211968081 is about 596.2432690458.

The spelling of 211968081 in words is "two hundred eleven million, nine hundred sixty-eight thousand, eighty-one".