721839680 has 28 divisors (see below), whose sum is σ = 1718881500. Its totient is φ = 288735744.

The previous prime is 721839673. The next prime is 721839683. The reversal of 721839680 is 86938127.

It can be written as a sum of positive squares in 2 ways, for example, as 350737984 + 371101696 = 18728^2 + 19264^2 .

It is not an unprimeable number, because it can be changed into a prime (721839683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1127555 + ... + 1128194.

It is an arithmetic number, because the mean of its divisors is an integer number (61388625).

Almost surely, 2^721839680 is an apocalyptic number.

It is an amenable number.

721839680 is an abundant number, since it is smaller than the sum of its proper divisors (997041820).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

721839680 is a wasteful number, since it uses less digits than its factorization.

721839680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2255766 (or 2255756 counting only the distinct ones).

The product of its (nonzero) digits is 145152, while the sum is 44.

The square root of 721839680 is about 26867.0742731694. The cubic root of 721839680 is about 897.0436658754.

The spelling of 721839680 in words is "seven hundred twenty-one million, eight hundred thirty-nine thousand, six hundred eighty".