721334646 has 20 divisors (see below), whose sum is σ = 1616324292. Its totient is φ = 240444828.

The previous prime is 721334597. The next prime is 721334651. The reversal of 721334646 is 646433127.

It is a happy number.

721334646 is a `hidden beast` number, since 7 + 2 + 1 + 3 + 3 + 4 + 646 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 721334646.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2226180 + ... + 2226503.

Almost surely, 2^721334646 is an apocalyptic number.

721334646 is an abundant number, since it is smaller than the sum of its proper divisors (894989646).

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

721334646 is a wasteful number, since it uses less digits than its factorization.

721334646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4452697 (or 4452688 counting only the distinct ones).

The product of its digits is 72576, while the sum is 36.

The square root of 721334646 is about 26857.6738754495. The cubic root of 721334646 is about 896.8344120018.

The spelling of 721334646 in words is "seven hundred twenty-one million, three hundred thirty-four thousand, six hundred forty-six".