7220991 has 4 divisors (see below), whose sum is σ = 9627992. Its totient is φ = 4813992.

The previous prime is 7220981. The next prime is 7220999. The reversal of 7220991 is 1990227.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1990227 = 3 ⋅663409.

It is not a de Polignac number, because 7220991 - 2²² = 3026687 is a prime.

It is a super-2 number, since 2×7220991² = 104285422044162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7220999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1203496 + ... + 1203501.

It is an arithmetic number, because the mean of its divisors is an integer number (2406998).

Almost surely, 2^7220991 is an apocalyptic number.

7220991 is a deficient number, since it is larger than the sum of its proper divisors (2407001).

7220991 is a wasteful number, since it uses less digits than its factorization.

7220991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2407000.

The product of its (nonzero) digits is 2268, while the sum is 30.

The square root of 7220991 is about 2687.1901681868. The cubic root of 7220991 is about 193.2853484427.

The spelling of 7220991 in words is "seven million, two hundred twenty thousand, nine hundred ninety-one".