721254481920 has 864 divisors, whose sum is σ = 2967945297408. Its totient is φ = 164603363328.

The previous prime is 721254481907. The next prime is 721254481973. The reversal of 721254481920 is 29184452127.

721254481920 is a `hidden beast` number, since 7 + 2 + 1 + 2 + 544 + 81 + 9 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (864).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1114767037 + ... + 1114767683.

It is an arithmetic number, because the mean of its divisors is an integer number (3435121872).

Almost surely, 2^721254481920 is an apocalyptic number.

721254481920 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 721254481920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1483972648704).

721254481920 is an abundant number, since it is smaller than the sum of its proper divisors (2246690815488).

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

721254481920 is an frugal number, since it uses more digits than its factorization.

721254481920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 708 (or 664 counting only the distinct ones).

The product of its (nonzero) digits is 322560, while the sum is 45.

The spelling of 721254481920 in words is "seven hundred twenty-one billion, two hundred fifty-four million, four hundred eighty-one thousand, nine hundred twenty".