221647745 has 8 divisors (see below), whose sum is σ = 290157120. Its totient is φ = 161198320.

The previous prime is 221647703. The next prime is 221647747. The reversal of 221647745 is 547746122.

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

It is not a de Polignac number, because 221647745 - 2¹⁰ = 221646721 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 221647699 and 221647708.

It is not an unprimeable number, because it can be changed into a prime (221647747) 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, 2014925 + ... + 2015034.

It is an arithmetic number, because the mean of its divisors is an integer number (36269640).

Almost surely, 2^221647745 is an apocalyptic number.

It is an amenable number.

221647745 is a deficient number, since it is larger than the sum of its proper divisors (68509375).

221647745 is a wasteful number, since it uses less digits than its factorization.

221647745 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4029975.

The product of its digits is 94080, while the sum is 38.

The square root of 221647745 is about 14887.8388290578. The cubic root of 221647745 is about 605.1844666648.

The spelling of 221647745 in words is "two hundred twenty-one million, six hundred forty-seven thousand, seven hundred forty-five".