721405672 has 32 divisors (see below), whose sum is σ = 1520023680. Its totient is φ = 318479040.

The previous prime is 721405651. The next prime is 721405721. The reversal of 721405672 is 276504127.

It is a super-2 number, since 2×721405672² = 1040852287187543168, which contains 22 as substring.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 148404 + ... + 153187.

It is an arithmetic number, because the mean of its divisors is an integer number (47500740).

Almost surely, 2^721405672 is an apocalyptic number.

It is an amenable number.

721405672 is an abundant number, since it is smaller than the sum of its proper divisors (798618008).

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

721405672 is a wasteful number, since it uses less digits than its factorization.

721405672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 301633 (or 301629 counting only the distinct ones).

The product of its (nonzero) digits is 23520, while the sum is 34.

The square root of 721405672 is about 26858.9961093113. The cubic root of 721405672 is about 896.8638465463.

Adding to 721405672 its reverse (276504127), we get a palindrome (997909799).

The spelling of 721405672 in words is "seven hundred twenty-one million, four hundred five thousand, six hundred seventy-two".