7221280 has 72 divisors (see below), whose sum is σ = 18802476. Its totient is φ = 2618880.

The previous prime is 7221259. The next prime is 7221281. The reversal of 7221280 is 821227.

7221280 = 335² + 336² + ... + 389².

It can be written as a sum of positive squares in 2 ways, for example, as 7203856 + 17424 = 2684^2 + 132^2 .

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (7221281) 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, 19174 + ... + 19546.

Almost surely, 2^7221280 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 7221280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9401238).

7221280 is an abundant number, since it is smaller than the sum of its proper divisors (11581196).

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

7221280 is a wasteful number, since it uses less digits than its factorization.

7221280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 410 (or 391 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 22.

The square root of 7221280 is about 2687.2439412900. The cubic root of 7221280 is about 193.2879269771.

It can be divided in two parts, 722 and 1280, that added together give a palindrome (2002).

The spelling of 7221280 in words is "seven million, two hundred twenty-one thousand, two hundred eighty".