721312532 has 6 divisors (see below), whose sum is σ = 1262296938. Its totient is φ = 360656264.

The previous prime is 721312531. The next prime is 721312597. The reversal of 721312532 is 235213127.

It can be written as a sum of positive squares in only one way, i.e., 456078736 + 265233796 = 21356^2 + 16286^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721312531) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90164063 + ... + 90164070.

It is an arithmetic number, because the mean of its divisors is an integer number (210382823).

Almost surely, 2^721312532 is an apocalyptic number.

It is an amenable number.

721312532 is a deficient number, since it is larger than the sum of its proper divisors (540984406).

721312532 is a wasteful number, since it uses less digits than its factorization.

721312532 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180328137 (or 180328135 counting only the distinct ones).

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

The square root of 721312532 is about 26857.2621836255. The cubic root of 721312532 is about 896.8252471391.

Adding to 721312532 its reverse (235213127), we get a palindrome (956525659).

The spelling of 721312532 in words is "seven hundred twenty-one million, three hundred twelve thousand, five hundred thirty-two".