721278252 has 72 divisors (see below), whose sum is σ = 1928725344. Its totient is φ = 226803456.

The previous prime is 721278251. The next prime is 721278263. The reversal of 721278252 is 252872127.

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 (721278251) 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, 54478 + ... + 66410.

It is an arithmetic number, because the mean of its divisors is an integer number (26787852).

Almost surely, 2^721278252 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 721278252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (964362672).

721278252 is an abundant number, since it is smaller than the sum of its proper divisors (1207447092).

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

721278252 is a wasteful number, since it uses less digits than its factorization.

721278252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12039 (or 12034 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 721278252 is about 26856.6239873890. The cubic root of 721278252 is about 896.8110398641.

The spelling of 721278252 in words is "seven hundred twenty-one million, two hundred seventy-eight thousand, two hundred fifty-two".