1561513241 has 4 divisors (see below), whose sum is σ = 1561635684. Its totient is φ = 1561390800.

The previous prime is 1561513237. The next prime is 1561513253. The reversal of 1561513241 is 1423151651.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 439531225 + 1121982016 = 20965^2 + 33496^2 .

It is a cyclic number.

It is not a de Polignac number, because 1561513241 - 2² = 1561513237 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1561513141) 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, 39530 + ... + 68451.

It is an arithmetic number, because the mean of its divisors is an integer number (390408921).

Almost surely, 2^1561513241 is an apocalyptic number.

It is an amenable number.

1561513241 is a deficient number, since it is larger than the sum of its proper divisors (122443).

1561513241 is a wasteful number, since it uses less digits than its factorization.

1561513241 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122442.

The product of its digits is 3600, while the sum is 29.

The square root of 1561513241 is about 39515.9871570988. The cubic root of 1561513241 is about 1160.1528833871.

Adding to 1561513241 its reverse (1423151651), we get a palindrome (2984664892).

The spelling of 1561513241 in words is "one billion, five hundred sixty-one million, five hundred thirteen thousand, two hundred forty-one".