15135221 has 4 divisors (see below), whose sum is σ = 15176172. Its totient is φ = 15094272.

The previous prime is 15135217. The next prime is 15135227. The reversal of 15135221 is 12253151.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12253151 = 43 ⋅284957.

It can be written as a sum of positive squares in 2 ways, for example, as 8940100 + 6195121 = 2990^2 + 2489^2 .

It is a cyclic number.

It is not a de Polignac number, because 15135221 - 2² = 15135217 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 15135193 and 15135202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (15135227) 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, 19916 + ... + 20661.

It is an arithmetic number, because the mean of its divisors is an integer number (3794043).

Almost surely, 2^15135221 is an apocalyptic number.

It is an amenable number.

15135221 is a deficient number, since it is larger than the sum of its proper divisors (40951).

15135221 is an equidigital number, since it uses as much as digits as its factorization.

15135221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40950.

The product of its digits is 300, while the sum is 20.

The square root of 15135221 is about 3890.4011361298. The cubic root of 15135221 is about 247.3600664615.

Adding to 15135221 its reverse (12253151), we get a palindrome (27388372).

The spelling of 15135221 in words is "fifteen million, one hundred thirty-five thousand, two hundred twenty-one".