721437 has 4 divisors (see below), whose sum is σ = 961920. Its totient is φ = 480956.

The previous prime is 721397. The next prime is 721439. The reversal of 721437 is 734127.

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 721437 - 2⁸ = 721181 is a prime.

It is a D-number.

721437 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721439) 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, 120237 + ... + 120242.

It is an arithmetic number, because the mean of its divisors is an integer number (240480).

2⁷²¹⁴³⁷ is an apocalyptic number.

It is an amenable number.

721437 is a deficient number, since it is larger than the sum of its proper divisors (240483).

721437 is a wasteful number, since it uses less digits than its factorization.

721437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240482.

The product of its digits is 1176, while the sum is 24.

The square root of 721437 is about 849.3744757173. The cubic root of 721437 is about 89.6876828860.

The spelling of 721437 in words is "seven hundred twenty-one thousand, four hundred thirty-seven".