221745657 has 8 divisors (see below), whose sum is σ = 337898176. Its totient is φ = 126711792.

The previous prime is 221745649. The next prime is 221745673. The reversal of 221745657 is 756547122.

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

It is not a de Polignac number, because 221745657 - 2³ = 221745649 is a prime.

It is a super-2 number, since 2×221745657² = 98342272796723298, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (221745647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5279638 + ... + 5279679.

It is an arithmetic number, because the mean of its divisors is an integer number (42237272).

Almost surely, 2^221745657 is an apocalyptic number.

It is an amenable number.

221745657 is a deficient number, since it is larger than the sum of its proper divisors (116152519).

221745657 is a wasteful number, since it uses less digits than its factorization.

221745657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10559327.

The product of its digits is 117600, while the sum is 39.

The square root of 221745657 is about 14891.1267874530. The cubic root of 221745657 is about 605.2735661478.

It can be divided in two parts, 2217 and 45657, that added together give a palindrome (47874).

The spelling of 221745657 in words is "two hundred twenty-one million, seven hundred forty-five thousand, six hundred fifty-seven".