157561009 has 2 divisors, whose sum is σ = 157561010. Its totient is φ = 157561008.

The previous prime is 157560959. The next prime is 157561021. The reversal of 157561009 is 900165751.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152399025 + 5161984 = 12345^2 + 2272^2 .

It is an emirp because it is prime and its reverse (900165751) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 157561009 - 2²⁵ = 124006577 is a prime.

It is not a weakly prime, because it can be changed into another prime (157561039) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78780504 + 78780505.

It is an arithmetic number, because the mean of its divisors is an integer number (78780505).

Almost surely, 2^157561009 is an apocalyptic number.

It is an amenable number.

157561009 is a deficient number, since it is larger than the sum of its proper divisors (1).

157561009 is an equidigital number, since it uses as much as digits as its factorization.

157561009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9450, while the sum is 34.

The square root of 157561009 is about 12552.3308194136. The cubic root of 157561009 is about 540.1108700107.

The spelling of 157561009 in words is "one hundred fifty-seven million, five hundred sixty-one thousand, nine".