211689987 has 16 divisors (see below), whose sum is σ = 292885152. Its totient is φ = 135889920.

The previous prime is 211689983. The next prime is 211689997. The reversal of 211689987 is 789986112.

It is not a de Polignac number, because 211689987 - 2² = 211689983 is a prime.

It is not an unprimeable number, because it can be changed into a prime (211689983) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 937 + ... + 20597.

It is an arithmetic number, because the mean of its divisors is an integer number (18305322).

Almost surely, 2^211689987 is an apocalyptic number.

211689987 is a deficient number, since it is larger than the sum of its proper divisors (81195165).

211689987 is a wasteful number, since it uses less digits than its factorization.

211689987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19798.

The product of its digits is 435456, while the sum is 51.

The square root of 211689987 is about 14549.5699936459. The cubic root of 211689987 is about 595.9824054908.

The spelling of 211689987 in words is "two hundred eleven million, six hundred eighty-nine thousand, nine hundred eighty-seven".