1561172313 has 16 divisors (see below), whose sum is σ = 2097100800. Its totient is φ = 1033038864.

The previous prime is 1561172299. The next prime is 1561172321. The reversal of 1561172313 is 3132711651.

It is not a de Polignac number, because 1561172313 - 2¹⁴ = 1561155929 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1561172363) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 261520 + ... + 267422.

It is an arithmetic number, because the mean of its divisors is an integer number (131068800).

Almost surely, 2^1561172313 is an apocalyptic number.

It is an amenable number.

1561172313 is a deficient number, since it is larger than the sum of its proper divisors (535928487).

1561172313 is a wasteful number, since it uses less digits than its factorization.

1561172313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6548.

The product of its digits is 3780, while the sum is 30.

The square root of 1561172313 is about 39511.6731232683. The cubic root of 1561172313 is about 1160.0684444850.

Adding to 1561172313 its reverse (3132711651), we get a palindrome (4693883964).

The spelling of 1561172313 in words is "one billion, five hundred sixty-one million, one hundred seventy-two thousand, three hundred thirteen".