221306747 has 8 divisors (see below), whose sum is σ = 225791280. Its totient is φ = 216833760.

The previous prime is 221306693. The next prime is 221306749. The reversal of 221306747 is 747603122.

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

It is a cyclic number.

It is not a de Polignac number, because 221306747 - 2¹⁰ = 221305723 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221306749) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 43097 + ... + 47957.

It is an arithmetic number, because the mean of its divisors is an integer number (28223910).

Almost surely, 2^221306747 is an apocalyptic number.

221306747 is a deficient number, since it is larger than the sum of its proper divisors (4484533).

221306747 is an equidigital number, since it uses as much as digits as its factorization.

221306747 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5773.

The product of its (nonzero) digits is 14112, while the sum is 32.

The square root of 221306747 is about 14876.3821878843. The cubic root of 221306747 is about 604.8739550272.

Adding to 221306747 its reverse (747603122), we get a palindrome (968909869).

The spelling of 221306747 in words is "two hundred twenty-one million, three hundred six thousand, seven hundred forty-seven".