721718209152 has 96 divisors (see below), whose sum is σ = 2078165212500. Its totient is φ = 240416833536.

The previous prime is 721718209073. The next prime is 721718209159. The reversal of 721718209152 is 251902817127.

It can be written as a sum of positive squares in 2 ways, for example, as 634163766336 + 87554442816 = 796344^2 + 295896^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 721718209098 and 721718209107.

It is not an unprimeable number, because it can be changed into a prime (721718209159) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1582224 + ... + 1986672.

Almost surely, 2^721718209152 is an apocalyptic number.

721718209152 is a gapful number since it is divisible by the number (72) 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 721718209152, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1039082606250).

721718209152 is an abundant number, since it is smaller than the sum of its proper divisors (1356447003348).

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

721718209152 is a wasteful number, since it uses less digits than its factorization.

721718209152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406018 (or 406003 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 45.

The spelling of 721718209152 in words is "seven hundred twenty-one billion, seven hundred eighteen million, two hundred nine thousand, one hundred fifty-two".