221631164 has 12 divisors (see below), whose sum is σ = 389865504. Its totient is φ = 110241024.

The previous prime is 221631131. The next prime is 221631247. The reversal of 221631164 is 461136122.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 142772 + ... + 144315.

It is an arithmetic number, because the mean of its divisors is an integer number (32488792).

Almost surely, 2^221631164 is an apocalyptic number.

It is an amenable number.

221631164 is a deficient number, since it is larger than the sum of its proper divisors (168234340).

221631164 is a wasteful number, since it uses less digits than its factorization.

221631164 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 287284 (or 287282 counting only the distinct ones).

The product of its digits is 1728, while the sum is 26.

The square root of 221631164 is about 14887.2819547424. The cubic root of 221631164 is about 605.1693754310.

Adding to 221631164 its reverse (461136122), we get a palindrome (682767286).

The spelling of 221631164 in words is "two hundred twenty-one million, six hundred thirty-one thousand, one hundred sixty-four".