816721732 has 24 divisors (see below), whose sum is σ = 1459126872. Its totient is φ = 399859200.

The previous prime is 816721729. The next prime is 816721739. The reversal of 816721732 is 237127618.

It can be written as a sum of positive squares in 4 ways, for example, as 15492096 + 801229636 = 3936^2 + 28306^2 .

It is a junction number, because it is equal to n+sod(n) for n = 816721691 and 816721700.

It is not an unprimeable number, because it can be changed into a prime (816721739) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 111132 + ... + 118252.

It is an arithmetic number, because the mean of its divisors is an integer number (60796953).

Almost surely, 2^816721732 is an apocalyptic number.

It is an amenable number.

816721732 is a deficient number, since it is larger than the sum of its proper divisors (642405140).

816721732 is a wasteful number, since it uses less digits than its factorization.

816721732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7719 (or 7717 counting only the distinct ones).

The product of its digits is 28224, while the sum is 37.

The square root of 816721732 is about 28578.3437588675. The cubic root of 816721732 is about 934.7411685016.

The spelling of 816721732 in words is "eight hundred sixteen million, seven hundred twenty-one thousand, seven hundred thirty-two".