1809409157 has 2 divisors, whose sum is σ = 1809409158. Its totient is φ = 1809409156.

The previous prime is 1809409139. The next prime is 1809409207. The reversal of 1809409157 is 7519049081.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1682148196 + 127260961 = 41014^2 + 11281^2 .

It is a cyclic number.

It is not a de Polignac number, because 1809409157 - 2¹⁸ = 1809147013 is a prime.

It is a super-2 number, since 2×1809409157² = 6547922994870901298, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1809409117) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 904704578 + 904704579.

It is an arithmetic number, because the mean of its divisors is an integer number (904704579).

Almost surely, 2^1809409157 is an apocalyptic number.

It is an amenable number.

1809409157 is a deficient number, since it is larger than the sum of its proper divisors (1).

1809409157 is an equidigital number, since it uses as much as digits as its factorization.

1809409157 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 90720, while the sum is 44.

The square root of 1809409157 is about 42537.1503159297. The cubic root of 1809409157 is about 1218.5562867154.

The spelling of 1809409157 in words is "one billion, eight hundred nine million, four hundred nine thousand, one hundred fifty-seven".