155566891 has 2 divisors, whose sum is σ = 155566892. Its totient is φ = 155566890.

The previous prime is 155566883. The next prime is 155566909. The reversal of 155566891 is 198665551.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 155566891 - 2³ = 155566883 is a prime.

It is not a weakly prime, because it can be changed into another prime (155566811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77783445 + 77783446.

It is an arithmetic number, because the mean of its divisors is an integer number (77783446).

Almost surely, 2^155566891 is an apocalyptic number.

155566891 is a deficient number, since it is larger than the sum of its proper divisors (1).

155566891 is an equidigital number, since it uses as much as digits as its factorization.

155566891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 324000, while the sum is 46.

The square root of 155566891 is about 12472.6457097121. The cubic root of 155566891 is about 537.8226118795.

The spelling of 155566891 in words is "one hundred fifty-five million, five hundred sixty-six thousand, eight hundred ninety-one".