221387287 has 6 divisors (see below), whose sum is σ = 243343184. Its totient is φ = 201261060.

The previous prime is 221387279. The next prime is 221387303. The reversal of 221387287 is 782783122.

It is not a de Polignac number, because 221387287 - 2³ = 221387279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221387237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 914703 + ... + 914944.

Almost surely, 2^221387287 is an apocalyptic number.

221387287 is a deficient number, since it is larger than the sum of its proper divisors (21955897).

221387287 is a wasteful number, since it uses less digits than its factorization.

221387287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829669 (or 1829658 counting only the distinct ones).

The product of its digits is 75264, while the sum is 40.

The square root of 221387287 is about 14879.0889170003. The cubic root of 221387287 is about 604.9473232373.

The spelling of 221387287 in words is "two hundred twenty-one million, three hundred eighty-seven thousand, two hundred eighty-seven".