15072221 has 4 divisors (see below), whose sum is σ = 15108444. Its totient is φ = 15036000.

The previous prime is 15072203. The next prime is 15072223. The reversal of 15072221 is 12227051.

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 972196 + 14100025 = 986^2 + 3755^2 .

It is a cyclic number.

It is not a de Polignac number, because 15072221 - 2²² = 10877917 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15072193 and 15072202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15072223) 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, 17480 + ... + 18321.

It is an arithmetic number, because the mean of its divisors is an integer number (3777111).

Almost surely, 2^15072221 is an apocalyptic number.

It is an amenable number.

15072221 is a deficient number, since it is larger than the sum of its proper divisors (36223).

15072221 is an equidigital number, since it uses as much as digits as its factorization.

15072221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36222.

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 15072221 is about 3882.2958413805. The cubic root of 15072221 is about 247.0163790108.

Adding to 15072221 its reverse (12227051), we get a palindrome (27299272).

The spelling of 15072221 in words is "fifteen million, seventy-two thousand, two hundred twenty-one".