731521 has 6 divisors (see below), whose sum is σ = 851010. Its totient is φ = 626976.

The previous prime is 731509. The next prime is 731531. The reversal of 731521 is 125137.

It can be written as a sum of positive squares in only one way, i.e., 705600 + 25921 = 840^2 + 161^2 .

It is not a de Polignac number, because 731521 - 2¹¹ = 729473 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 (731501) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7416 + ... + 7513.

It is an arithmetic number, because the mean of its divisors is an integer number (141835).

2⁷³¹⁵²¹ is an apocalyptic number.

It is an amenable number.

731521 is a deficient number, since it is larger than the sum of its proper divisors (119489).

731521 is a wasteful number, since it uses less digits than its factorization.

731521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14943 (or 14936 counting only the distinct ones).

The product of its digits is 210, while the sum is 19.

The square root of 731521 is about 855.2900092951. The cubic root of 731521 is about 90.1036254964.

Adding to 731521 its reverse (125137), we get a palindrome (856658).

It can be divided in two parts, 73152 and 1, that added together give a triangular number (73153 = T₃₈₂).

The spelling of 731521 in words is "seven hundred thirty-one thousand, five hundred twenty-one".