155144021 has 4 divisors (see below), whose sum is σ = 155246112. Its totient is φ = 155041932.

The previous prime is 155143909. The next prime is 155144051. The reversal of 155144021 is 120441551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 120441551 = 19 ⋅6339029.

It is a cyclic number.

It is not a de Polignac number, because 155144021 - 2¹⁸ = 154881877 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (155144051) 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 in 3 ways as a sum of consecutive naturals, for example, 48731 + ... + 51816.

It is an arithmetic number, because the mean of its divisors is an integer number (38811528).

Almost surely, 2^155144021 is an apocalyptic number.

It is an amenable number.

155144021 is a deficient number, since it is larger than the sum of its proper divisors (102091).

155144021 is a wasteful number, since it uses less digits than its factorization.

155144021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102090.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 155144021 is about 12455.6822775792. The cubic root of 155144021 is about 537.3348572166.

Adding to 155144021 its reverse (120441551), we get a palindrome (275585572).

The spelling of 155144021 in words is "one hundred fifty-five million, one hundred forty-four thousand, twenty-one".