721447 has 4 divisors (see below), whose sum is σ = 733336. Its totient is φ = 709560.

The previous prime is 721439. The next prime is 721451. The reversal of 721447 is 744127.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 721447 - 2³ = 721439 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721547) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5853 + ... + 5974.

It is an arithmetic number, because the mean of its divisors is an integer number (183334).

2⁷²¹⁴⁴⁷ is an apocalyptic number.

721447 is a deficient number, since it is larger than the sum of its proper divisors (11889).

721447 is a wasteful number, since it uses less digits than its factorization.

721447 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11888.

The product of its digits is 1568, while the sum is 25.

The square root of 721447 is about 849.3803623819. The cubic root of 721447 is about 89.6880972778.

The spelling of 721447 in words is "seven hundred twenty-one thousand, four hundred forty-seven", and thus it is an iban number.