721135872 has 180 divisors, whose sum is σ = 2181397680. Its totient is φ = 236915712.

The previous prime is 721135867. The next prime is 721135873. The reversal of 721135872 is 278531127.

721135872 is a `hidden beast` number, since 72 + 1 + 1 + 3 + 587 + 2 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (721135873) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1720879 + ... + 1721297.

It is an arithmetic number, because the mean of its divisors is an integer number (12118876).

Almost surely, 2^721135872 is an apocalyptic number.

721135872 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 721135872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1090698840).

721135872 is an abundant number, since it is smaller than the sum of its proper divisors (1460261808).

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

721135872 is an equidigital number, since it uses as much as digits as its factorization.

721135872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530 (or 507 counting only the distinct ones).

The product of its digits is 23520, while the sum is 36.

The square root of 721135872 is about 26853.9731138616. The cubic root of 721135872 is about 896.7520259499.

Adding to 721135872 its reverse (278531127), we get a palindrome (999666999).

The spelling of 721135872 in words is "seven hundred twenty-one million, one hundred thirty-five thousand, eight hundred seventy-two".