15221291 has 4 divisors (see below), whose sum is σ = 15592584. Its totient is φ = 14850000.

The previous prime is 15221281. The next prime is 15221293. The reversal of 15221291 is 19212251.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19212251 = 281 ⋅68371.

It is a cyclic number.

It is not a de Polignac number, because 15221291 - 2¹⁰ = 15220267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (15221293) 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, 185585 + ... + 185666.

It is an arithmetic number, because the mean of its divisors is an integer number (3898146).

Almost surely, 2^15221291 is an apocalyptic number.

15221291 is a deficient number, since it is larger than the sum of its proper divisors (371293).

15221291 is an equidigital number, since it uses as much as digits as its factorization.

15221291 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 371292.

The product of its digits is 360, while the sum is 23.

The square root of 15221291 is about 3901.4472955558. The cubic root of 15221291 is about 247.8280708719.

The spelling of 15221291 in words is "fifteen million, two hundred twenty-one thousand, two hundred ninety-one".