15561225 has 72 divisors (see below), whose sum is σ = 30331392. Its totient is φ = 7603200.

The previous prime is 15561211. The next prime is 15561229. The reversal of 15561225 is 52216551.

15561225 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 15561225 - 2⁵ = 15561193 is a prime.

It is not an unprimeable number, because it can be changed into a prime (15561229) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 160377 + ... + 160473.

Almost surely, 2^15561225 is an apocalyptic number.

15561225 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

15561225 is a deficient number, since it is larger than the sum of its proper divisors (14770167).

15561225 is a wasteful number, since it uses less digits than its factorization.

15561225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167 (or 159 counting only the distinct ones).

The product of its digits is 3000, while the sum is 27.

The square root of 15561225 is about 3944.7718565210. The cubic root of 15561225 is about 249.6594028517.

Adding to 15561225 its reverse (52216551), we get a palindrome (67777776).

The spelling of 15561225 in words is "fifteen million, five hundred sixty-one thousand, two hundred twenty-five".