155840389 has 2 divisors, whose sum is σ = 155840390. Its totient is φ = 155840388.

The previous prime is 155840383. The next prime is 155840407. The reversal of 155840389 is 983048551.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 136188900 + 19651489 = 11670^2 + 4433^2 .

It is an emirp because it is prime and its reverse (983048551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155840389 - 2¹⁷ = 155709317 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (155840383) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77920194 + 77920195.

It is an arithmetic number, because the mean of its divisors is an integer number (77920195).

Almost surely, 2^155840389 is an apocalyptic number.

It is an amenable number.

155840389 is a deficient number, since it is larger than the sum of its proper divisors (1).

155840389 is an equidigital number, since it uses as much as digits as its factorization.

155840389 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 172800, while the sum is 43.

The square root of 155840389 is about 12483.6048079070. The cubic root of 155840389 is about 538.1376045525.

The spelling of 155840389 in words is "one hundred fifty-five million, eight hundred forty thousand, three hundred eighty-nine".