721667732 has 12 divisors (see below), whose sum is σ = 1293721716. Its totient is φ = 352032960.

The previous prime is 721667719. The next prime is 721667761. The reversal of 721667732 is 237766127.

It can be written as a sum of positive squares in 2 ways, for example, as 61999876 + 659667856 = 7874^2 + 25684^2 .

It is a Harshad number since it is a multiple of its sum of digits (41).

It is a self number, because there is not a number n which added to its sum of digits gives 721667732.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2200043 + ... + 2200370.

It is an arithmetic number, because the mean of its divisors is an integer number (107810143).

Almost surely, 2^721667732 is an apocalyptic number.

It is an amenable number.

721667732 is a deficient number, since it is larger than the sum of its proper divisors (572053984).

721667732 is a wasteful number, since it uses less digits than its factorization.

721667732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4400458 (or 4400456 counting only the distinct ones).

The product of its digits is 148176, while the sum is 41.

The square root of 721667732 is about 26863.8741063161. The cubic root of 721667732 is about 896.9724325542.

The spelling of 721667732 in words is "seven hundred twenty-one million, six hundred sixty-seven thousand, seven hundred thirty-two".