155442139 has 2 divisors, whose sum is σ = 155442140. Its totient is φ = 155442138.

The previous prime is 155442127. The next prime is 155442187. The reversal of 155442139 is 931244551.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 155442139 - 2⁵ = 155442107 is a prime.

It is not a weakly prime, because it can be changed into another prime (155442739) 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, 77721069 + 77721070.

It is an arithmetic number, because the mean of its divisors is an integer number (77721070).

Almost surely, 2^155442139 is an apocalyptic number.

155442139 is a deficient number, since it is larger than the sum of its proper divisors (1).

155442139 is an equidigital number, since it uses as much as digits as its factorization.

155442139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21600, while the sum is 34.

The square root of 155442139 is about 12467.6436827494. The cubic root of 155442139 is about 537.6788100958.

The spelling of 155442139 in words is "one hundred fifty-five million, four hundred forty-two thousand, one hundred thirty-nine".