221888387 has 8 divisors (see below), whose sum is σ = 254307936. Its totient is φ = 189649152.

The previous prime is 221888347. The next prime is 221888393. The reversal of 221888387 is 783888122.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-221888387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221888347) 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 7 ways as a sum of consecutive naturals, for example, 42428 + ... + 47369.

It is an arithmetic number, because the mean of its divisors is an integer number (31788492).

Almost surely, 2^221888387 is an apocalyptic number.

221888387 is a deficient number, since it is larger than the sum of its proper divisors (32419549).

221888387 is an equidigital number, since it uses as much as digits as its factorization.

221888387 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90157.

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

The square root of 221888387 is about 14895.9184678220. The cubic root of 221888387 is about 605.4034028390.

It can be divided in two parts, 22 and 1888387, that multiplied together give a palindrome (41544514).

The spelling of 221888387 in words is "two hundred twenty-one million, eight hundred eighty-eight thousand, three hundred eighty-seven".