221765216 has 24 divisors (see below), whose sum is σ = 441511560. Its totient is φ = 109635328.

The previous prime is 221765189. The next prime is 221765231. The reversal of 221765216 is 612567122.

It is a super-2 number, since 2×221765216² = 98359622055053312, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

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, 36086 + ... + 41781.

It is an arithmetic number, because the mean of its divisors is an integer number (18396315).

Almost surely, 2^221765216 is an apocalyptic number.

It is an amenable number.

221765216 is a deficient number, since it is larger than the sum of its proper divisors (219746344).

221765216 is an equidigital number, since it uses as much as digits as its factorization.

221765216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77966 (or 77958 counting only the distinct ones).

The product of its digits is 10080, while the sum is 32.

The square root of 221765216 is about 14891.7835063501. The cubic root of 221765216 is about 605.2913616074.

The spelling of 221765216 in words is "two hundred twenty-one million, seven hundred sixty-five thousand, two hundred sixteen".