1561258157 has 2 divisors, whose sum is σ = 1561258158. Its totient is φ = 1561258156.

The previous prime is 1561258133. The next prime is 1561258163. The reversal of 1561258157 is 7518521651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1421214601 + 140043556 = 37699^2 + 11834^2 .

It is an emirp because it is prime and its reverse (7518521651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1561258157 - 2⁶ = 1561258093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1561254157) 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, 780629078 + 780629079.

It is an arithmetic number, because the mean of its divisors is an integer number (780629079).

Almost surely, 2^1561258157 is an apocalyptic number.

It is an amenable number.

1561258157 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561258157 is an equidigital number, since it uses as much as digits as its factorization.

1561258157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 84000, while the sum is 41.

The square root of 1561258157 is about 39512.7594202177. The cubic root of 1561258157 is about 1160.0897069447.

The spelling of 1561258157 in words is "one billion, five hundred sixty-one million, two hundred fifty-eight thousand, one hundred fifty-seven".