155891256809 has 2 divisors, whose sum is σ = 155891256810. Its totient is φ = 155891256808.

The previous prime is 155891256799. The next prime is 155891256883. The reversal of 155891256809 is 908652198551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 114381269209 + 41509987600 = 338203^2 + 203740^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-155891256809 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (155891256889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77945628404 + 77945628405.

It is an arithmetic number, because the mean of its divisors is an integer number (77945628405).

Almost surely, 2^155891256809 is an apocalyptic number.

It is an amenable number.

155891256809 is a deficient number, since it is larger than the sum of its proper divisors (1).

155891256809 is an equidigital number, since it uses as much as digits as its factorization.

155891256809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776000, while the sum is 59.

The spelling of 155891256809 in words is "one hundred fifty-five billion, eight hundred ninety-one million, two hundred fifty-six thousand, eight hundred nine".