221216460 has 24 divisors (see below), whose sum is σ = 619406256. Its totient is φ = 58991040.

The previous prime is 221216459. The next prime is 221216473. The reversal of 221216460 is 64612122.

It is a self number, because there is not a number n which added to its sum of digits gives 221216460.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1843411 + ... + 1843530.

It is an arithmetic number, because the mean of its divisors is an integer number (25808594).

Almost surely, 2^221216460 is an apocalyptic number.

221216460 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

221216460 is an abundant number, since it is smaller than the sum of its proper divisors (398189796).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

221216460 is a wasteful number, since it uses less digits than its factorization.

221216460 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3686953 (or 3686951 counting only the distinct ones).

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 221216460 is about 14873.3473031460. The cubic root of 221216460 is about 604.7916865861.

Adding to 221216460 its reverse (64612122), we get a palindrome (285828582).

The spelling of 221216460 in words is "two hundred twenty-one million, two hundred sixteen thousand, four hundred sixty".