745221 has 4 divisors (see below), whose sum is σ = 993632. Its totient is φ = 496812.

The previous prime is 745201. The next prime is 745231. The reversal of 745221 is 122547.

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, and also an emirpimes, since its reverse is a distinct semiprime: 122547 = 3 ⋅40849.

It is not a de Polignac number, because 745221 - 2⁵ = 745189 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (745201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 124201 + ... + 124206.

It is an arithmetic number, because the mean of its divisors is an integer number (248408).

2⁷⁴⁵²²¹ is an apocalyptic number.

It is an amenable number.

745221 is a deficient number, since it is larger than the sum of its proper divisors (248411).

745221 is a wasteful number, since it uses less digits than its factorization.

745221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248410.

The product of its digits is 560, while the sum is 21.

The square root of 745221 is about 863.2618374514. The cubic root of 745221 is about 90.6626400917.

Adding to 745221 its reverse (122547), we get a palindrome (867768).

The spelling of 745221 in words is "seven hundred forty-five thousand, two hundred twenty-one".