211999987 has 4 divisors (see below), whose sum is σ = 213269616. Its totient is φ = 210730360.

The previous prime is 211999969. The next prime is 212000003. The reversal of 211999987 is 789999112.

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

It is a cyclic number.

It is not a de Polignac number, because 211999987 - 2¹⁵ = 211967219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (211999927) 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, 634564 + ... + 634897.

It is an arithmetic number, because the mean of its divisors is an integer number (53317404).

Almost surely, 2^211999987 is an apocalyptic number.

211999987 is a deficient number, since it is larger than the sum of its proper divisors (1269629).

211999987 is a wasteful number, since it uses less digits than its factorization.

211999987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1269628.

The product of its digits is 734832, while the sum is 55.

The square root of 211999987 is about 14560.2193321392. The cubic root of 211999987 is about 596.2731835864.

The spelling of 211999987 in words is "two hundred eleven million, nine hundred ninety-nine thousand, nine hundred eighty-seven".