221764393 has 4 divisors (see below), whose sum is σ = 221904000. Its totient is φ = 221624788.

The previous prime is 221764391. The next prime is 221764399. The reversal of 221764393 is 393467122.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 221764393 - 2¹ = 221764391 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (221764391) 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 3 ways as a sum of consecutive naturals, for example, 67393 + ... + 70606.

It is an arithmetic number, because the mean of its divisors is an integer number (55476000).

Almost surely, 2^221764393 is an apocalyptic number.

It is an amenable number.

221764393 is a deficient number, since it is larger than the sum of its proper divisors (139607).

221764393 is a wasteful number, since it uses less digits than its factorization.

221764393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139606.

The product of its digits is 54432, while the sum is 37.

The square root of 221764393 is about 14891.7558736369. The cubic root of 221764393 is about 605.2906128344.

It can be divided in two parts, 22176 and 4393, that added together give a square (26569 = 163²).

The spelling of 221764393 in words is "two hundred twenty-one million, seven hundred sixty-four thousand, three hundred ninety-three".