1561225115 has 4 divisors (see below), whose sum is σ = 1873470144. Its totient is φ = 1248980088.

The previous prime is 1561225109. The next prime is 1561225139. The reversal of 1561225115 is 5115221651.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5115221651 = 109 ⋅46928639.

It is a cyclic number.

It is not a de Polignac number, because 1561225115 - 2⁸ = 1561224859 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 156122507 + ... + 156122516.

It is an arithmetic number, because the mean of its divisors is an integer number (468367536).

Almost surely, 2^1561225115 is an apocalyptic number.

1561225115 is a deficient number, since it is larger than the sum of its proper divisors (312245029).

1561225115 is an equidigital number, since it uses as much as digits as its factorization.

1561225115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 312245028.

The product of its digits is 3000, while the sum is 29.

The square root of 1561225115 is about 39512.3412999027. The cubic root of 1561225115 is about 1160.0815229566.

Adding to 1561225115 its reverse (5115221651), we get a palindrome (6676446766).

The spelling of 1561225115 in words is "one billion, five hundred sixty-one million, two hundred twenty-five thousand, one hundred fifteen".