721340672 has 54 divisors (see below), whose sum is σ = 1559235762. Its totient is φ = 332906496.

The previous prime is 721340671. The next prime is 721340699. The reversal of 721340672 is 276043127.

It can be written as a sum of positive squares in 3 ways, for example, as 48664576 + 672676096 = 6976^2 + 25936^2 .

It is a super-3 number, since 3×721340672³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721340671) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 34928 + ... + 51600.

Almost surely, 2^721340672 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 721340672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (779617881).

721340672 is an abundant number, since it is smaller than the sum of its proper divisors (837895090).

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

721340672 is a wasteful number, since it uses less digits than its factorization.

721340672 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16715 (or 16688 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 32.

The square root of 721340672 is about 26857.7860591673. The cubic root of 721340672 is about 896.8369093674.

Adding to 721340672 its reverse (276043127), we get a palindrome (997383799).

The spelling of 721340672 in words is "seven hundred twenty-one million, three hundred forty thousand, six hundred seventy-two".