745721 has 4 divisors (see below), whose sum is σ = 748944. Its totient is φ = 742500.

The previous prime is 745711. The next prime is 745727. The reversal of 745721 is 127547.

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 745721 - 2¹⁸ = 483577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (745727) 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, 1235 + ... + 1736.

It is an arithmetic number, because the mean of its divisors is an integer number (187236).

2⁷⁴⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

745721 is a deficient number, since it is larger than the sum of its proper divisors (3223).

745721 is a wasteful number, since it uses less digits than its factorization.

745721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3222.

The product of its digits is 1960, while the sum is 26.

The square root of 745721 is about 863.5513881640. The cubic root of 745721 is about 90.6829120136.

The spelling of 745721 in words is "seven hundred forty-five thousand, seven hundred twenty-one".