7220391 has 16 divisors (see below), whose sum is σ = 10044000. Its totient is φ = 4608128.

The previous prime is 7220383. The next prime is 7220407. The reversal of 7220391 is 1930227.

It is a cyclic number.

It is not a de Polignac number, because 7220391 - 2³ = 7220383 is a prime.

7220391 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7220371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12685 + ... + 13241.

It is an arithmetic number, because the mean of its divisors is an integer number (627750).

Almost surely, 2^7220391 is an apocalyptic number.

7220391 is a deficient number, since it is larger than the sum of its proper divisors (2823609).

7220391 is a wasteful number, since it uses less digits than its factorization.

7220391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 738.

The product of its (nonzero) digits is 756, while the sum is 24.

The square root of 7220391 is about 2687.0785250900. The cubic root of 7220391 is about 193.2799948644.

The spelling of 7220391 in words is "seven million, two hundred twenty thousand, three hundred ninety-one".