721965921408 has 96 divisors (see below), whose sum is σ = 2078232109200. Its totient is φ = 240574225920.

The previous prime is 721965921403. The next prime is 721965921409. The reversal of 721965921408 is 804129569127.

It is a happy number.

721965921408 is a `hidden beast` number, since 7 + 2 + 1 + 9 + 6 + 592 + 1 + 40 + 8 = 666.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (721965921403) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 3364603 + ... + 3572741.

Almost surely, 2^721965921408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721965921408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1039116054600).

721965921408 is an abundant number, since it is smaller than the sum of its proper divisors (1356266187792).

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

721965921408 is a wasteful number, since it uses less digits than its factorization.

721965921408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 211170 (or 211155 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 721965921408 in words is "seven hundred twenty-one billion, nine hundred sixty-five million, nine hundred twenty-one thousand, four hundred eight".