721132531 has 16 divisors (see below), whose sum is σ = 853482240. Its totient is φ = 596161440.

The previous prime is 721132523. The next prime is 721132541. The reversal of 721132531 is 135231127.

It is a happy number.

It is not a de Polignac number, because 721132531 - 2³ = 721132523 is a prime.

It is a super-2 number, since 2×721132531² = 1040064254532931922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 721132496 and 721132505.

It is not an unprimeable number, because it can be changed into a prime (721132541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 337336 + ... + 339466.

It is an arithmetic number, because the mean of its divisors is an integer number (53342640).

Almost surely, 2^721132531 is an apocalyptic number.

721132531 is a deficient number, since it is larger than the sum of its proper divisors (132349709).

721132531 is a wasteful number, since it uses less digits than its factorization.

721132531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3834.

The product of its digits is 1260, while the sum is 25.

The square root of 721132531 is about 26853.9109069796. The cubic root of 721132531 is about 896.7506410731.

Adding to 721132531 its reverse (135231127), we get a palindrome (856363658).

The spelling of 721132531 in words is "seven hundred twenty-one million, one hundred thirty-two thousand, five hundred thirty-one".