211639969 has 2 divisors, whose sum is σ = 211639970. Its totient is φ = 211639968.

The previous prime is 211639949. The next prime is 211640003. The reversal of 211639969 is 969936112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 211557025 + 82944 = 14545^2 + 288^2 .

It is a cyclic number.

It is not a de Polignac number, because 211639969 - 2²³ = 203251361 is a prime.

It is a super-2 number, since 2×211639969² = 89582952956641922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (211639949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105819984 + 105819985.

It is an arithmetic number, because the mean of its divisors is an integer number (105819985).

Almost surely, 2^211639969 is an apocalyptic number.

It is an amenable number.

211639969 is a deficient number, since it is larger than the sum of its proper divisors (1).

211639969 is an equidigital number, since it uses as much as digits as its factorization.

211639969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 157464, while the sum is 46.

The square root of 211639969 is about 14547.8510096852. The cubic root of 211639969 is about 595.9354623225.

The spelling of 211639969 in words is "two hundred eleven million, six hundred thirty-nine thousand, nine hundred sixty-nine".