15561145 has 8 divisors (see below), whose sum is σ = 18810504. Its totient is φ = 12357504.

The previous prime is 15561131. The next prime is 15561157. The reversal of 15561145 is 54116551.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1212201 + 14348944 = 1101^2 + 3788^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-15561145 is a prime.

It is a super-2 number, since 2×15561145² = 484298467422050, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 10674 + ... + 12043.

It is an arithmetic number, because the mean of its divisors is an integer number (2351313).

Almost surely, 2^15561145 is an apocalyptic number.

It is an amenable number.

15561145 is a deficient number, since it is larger than the sum of its proper divisors (3249359).

15561145 is a wasteful number, since it uses less digits than its factorization.

15561145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22859.

The product of its digits is 3000, while the sum is 28.

The square root of 15561145 is about 3944.7617165046. The cubic root of 15561145 is about 249.6589750194.

Adding to 15561145 its reverse (54116551), we get a palindrome (69677696).

It can be divided in two parts, 1556 and 1145, that added together give a triangular number (2701 = T₇₃).

The spelling of 15561145 in words is "fifteen million, five hundred sixty-one thousand, one hundred forty-five".