721087776 has 144 divisors (see below), whose sum is σ = 2241727488. Its totient is φ = 218880000.

The previous prime is 721087739. The next prime is 721087777. The reversal of 721087776 is 677780127.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (721087777) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 149401 + ... + 154151.

It is an arithmetic number, because the mean of its divisors is an integer number (15567552).

Almost surely, 2^721087776 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 721087776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1120863744).

721087776 is an abundant number, since it is smaller than the sum of its proper divisors (1520639712).

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

721087776 is a wasteful number, since it uses less digits than its factorization.

721087776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4815 (or 4804 counting only the distinct ones).

The product of its (nonzero) digits is 230496, while the sum is 45.

The square root of 721087776 is about 26853.0775889841. The cubic root of 721087776 is about 896.7320892796.

The spelling of 721087776 in words is "seven hundred twenty-one million, eighty-seven thousand, seven hundred seventy-six".