211971647 has 2 divisors, whose sum is σ = 211971648. Its totient is φ = 211971646.

The previous prime is 211971637. The next prime is 211971653. The reversal of 211971647 is 746179112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 211971647 - 2¹⁰ = 211970623 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 211971647.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211971607) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105985823 + 105985824.

It is an arithmetic number, because the mean of its divisors is an integer number (105985824).

Almost surely, 2^211971647 is an apocalyptic number.

211971647 is a deficient number, since it is larger than the sum of its proper divisors (1).

211971647 is an equidigital number, since it uses as much as digits as its factorization.

211971647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 21168, while the sum is 38.

The square root of 211971647 is about 14559.2460999875. The cubic root of 211971647 is about 596.2466126177.

The spelling of 211971647 in words is "two hundred eleven million, nine hundred seventy-one thousand, six hundred forty-seven".