7139221 has 4 divisors (see below), whose sum is σ = 7152172. Its totient is φ = 7126272.

The previous prime is 7139219. The next prime is 7139273. The reversal of 7139221 is 1229317.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5904900 + 1234321 = 2430^2 + 1111^2 .

It is a cyclic number.

It is not a de Polignac number, because 7139221 - 2¹ = 7139219 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7139521) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5610 + ... + 6763.

It is an arithmetic number, because the mean of its divisors is an integer number (1788043).

Almost surely, 2^7139221 is an apocalyptic number.

It is an amenable number.

7139221 is a deficient number, since it is larger than the sum of its proper divisors (12951).

7139221 is a wasteful number, since it uses less digits than its factorization.

7139221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12950.

The product of its digits is 756, while the sum is 25.

The square root of 7139221 is about 2671.9320724899. The cubic root of 7139221 is about 192.5529937868.

The spelling of 7139221 in words is "seven million, one hundred thirty-nine thousand, two hundred twenty-one".