155440123 has 2 divisors, whose sum is σ = 155440124. Its totient is φ = 155440122.

The previous prime is 155440097. The next prime is 155440133. The reversal of 155440123 is 321044551.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (321044551) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 155440123 - 2⁵ = 155440091 is a prime.

It is not a weakly prime, because it can be changed into another prime (155440133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 77720061 + 77720062.

It is an arithmetic number, because the mean of its divisors is an integer number (77720062).

Almost surely, 2^155440123 is an apocalyptic number.

155440123 is a deficient number, since it is larger than the sum of its proper divisors (1).

155440123 is an equidigital number, since it uses as much as digits as its factorization.

155440123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2400, while the sum is 25.

The square root of 155440123 is about 12467.5628332084. The cubic root of 155440123 is about 537.6764856185.

Adding to 155440123 its reverse (321044551), we get a palindrome (476484674).

The spelling of 155440123 in words is "one hundred fifty-five million, four hundred forty thousand, one hundred twenty-three".