211947121 has 4 divisors (see below), whose sum is σ = 213891700. Its totient is φ = 210002544.

The previous prime is 211947119. The next prime is 211947149. The reversal of 211947121 is 121749112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 178596496 + 33350625 = 13364^2 + 5775^2 .

It is a cyclic number.

It is not a de Polignac number, because 211947121 - 2¹ = 211947119 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 211947121.

It is not an unprimeable number, because it can be changed into a prime (211947191) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 972126 + ... + 972343.

It is an arithmetic number, because the mean of its divisors is an integer number (53472925).

Almost surely, 2^211947121 is an apocalyptic number.

It is an amenable number.

211947121 is a deficient number, since it is larger than the sum of its proper divisors (1944579).

211947121 is a wasteful number, since it uses less digits than its factorization.

211947121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1944578.

The product of its digits is 1008, while the sum is 28.

The square root of 211947121 is about 14558.4037929987. The cubic root of 211947121 is about 596.2236156608.

The spelling of 211947121 in words is "two hundred eleven million, nine hundred forty-seven thousand, one hundred twenty-one".