221838887 has 4 divisors (see below), whose sum is σ = 231484080. Its totient is φ = 212193696.

The previous prime is 221838863. The next prime is 221838913. The reversal of 221838887 is 788838122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 788838122 = 2 ⋅394419061.

It is a cyclic number.

It is not a de Polignac number, because 221838887 - 2¹⁶ = 221773351 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 (221838847) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4822562 + ... + 4822607.

It is an arithmetic number, because the mean of its divisors is an integer number (57871020).

Almost surely, 2^221838887 is an apocalyptic number.

221838887 is a deficient number, since it is larger than the sum of its proper divisors (9645193).

221838887 is an equidigital number, since it uses as much as digits as its factorization.

221838887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9645192.

The product of its digits is 344064, while the sum is 47.

The square root of 221838887 is about 14894.2568461807. The cubic root of 221838887 is about 605.3583806583.

The spelling of 221838887 in words is "two hundred twenty-one million, eight hundred thirty-eight thousand, eight hundred eighty-seven".