221221465 has 16 divisors (see below), whose sum is σ = 280465920. Its totient is φ = 167045760.

The previous prime is 221221457. The next prime is 221221499. The reversal of 221221465 is 564122122.

It is not a de Polignac number, because 221221465 - 2³ = 221221457 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22552 + ... + 30838.

It is an arithmetic number, because the mean of its divisors is an integer number (17529120).

Almost surely, 2^221221465 is an apocalyptic number.

It is an amenable number.

221221465 is a deficient number, since it is larger than the sum of its proper divisors (59244455).

221221465 is a wasteful number, since it uses less digits than its factorization.

221221465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8592.

The product of its digits is 1920, while the sum is 25.

The square root of 221221465 is about 14873.5155561824. The cubic root of 221221465 is about 604.7962476686.

Adding to 221221465 its reverse (564122122), we get a palindrome (785343587).

The spelling of 221221465 in words is "two hundred twenty-one million, two hundred twenty-one thousand, four hundred sixty-five".