731340521 has 4 divisors (see below), whose sum is σ = 738880212. Its totient is φ = 723800832.

The previous prime is 731340503. The next prime is 731340523. The reversal of 731340521 is 125043137.

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

It can be written as a sum of positive squares in 2 ways, for example, as 231192025 + 500148496 = 15205^2 + 22364^2 .

It is a cyclic number.

It is not a de Polignac number, because 731340521 - 2¹⁸ = 731078377 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (731340523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3769700 + ... + 3769893.

It is an arithmetic number, because the mean of its divisors is an integer number (184720053).

Almost surely, 2^731340521 is an apocalyptic number.

It is an amenable number.

731340521 is a deficient number, since it is larger than the sum of its proper divisors (7539691).

731340521 is an equidigital number, since it uses as much as digits as its factorization.

731340521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7539690.

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 731340521 is about 27043.3082480676. The cubic root of 731340521 is about 900.9621484113.

Adding to 731340521 its reverse (125043137), we get a palindrome (856383658).

The spelling of 731340521 in words is "seven hundred thirty-one million, three hundred forty thousand, five hundred twenty-one".