721434 has 32 divisors (see below), whose sum is σ = 1676160. Its totient is φ = 202752.

The previous prime is 721397. The next prime is 721439. The reversal of 721434 is 434127.

It is a super-3 number, since 3×721434³ = 1126447804433323512, which contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 721434.

It is not an unprimeable number, because it can be changed into a prime (721439) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3642 + ... + 3834.

It is an arithmetic number, because the mean of its divisors is an integer number (52380).

2⁷²¹⁴³⁴ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721434, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (838080).

721434 is an abundant number, since it is smaller than the sum of its proper divisors (954726).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721434 is a wasteful number, since it uses less digits than its factorization.

721434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 294.

The product of its digits is 672, while the sum is 21.

The square root of 721434 is about 849.3727097099. The cubic root of 721434 is about 89.6875585677.

The spelling of 721434 in words is "seven hundred twenty-one thousand, four hundred thirty-four".