1561262617 has 2 divisors, whose sum is σ = 1561262618. Its totient is φ = 1561262616.

The previous prime is 1561262603. The next prime is 1561262621. The reversal of 1561262617 is 7162621651.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 997864921 + 563397696 = 31589^2 + 23736^2 .

It is an emirp because it is prime and its reverse (7162621651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1561262617 - 2¹⁵ = 1561229849 is a prime.

It is not a weakly prime, because it can be changed into another prime (1561262687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780631308 + 780631309.

It is an arithmetic number, because the mean of its divisors is an integer number (780631309).

Almost surely, 2^1561262617 is an apocalyptic number.

It is an amenable number.

1561262617 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561262617 is an equidigital number, since it uses as much as digits as its factorization.

1561262617 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 37.

The square root of 1561262617 is about 39512.8158576429. The cubic root of 1561262617 is about 1160.0908116083.

The spelling of 1561262617 in words is "one billion, five hundred sixty-one million, two hundred sixty-two thousand, six hundred seventeen".