1243120155 has 32 divisors (see below), whose sum is σ = 2150820864. Its totient is φ = 610715136.

The previous prime is 1243120027. The next prime is 1243120199. The reversal of 1243120155 is 5510213421.

It is a happy number.

It is not a de Polignac number, because 1243120155 - 2⁷ = 1243120027 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 39877 + ... + 63846.

It is an arithmetic number, because the mean of its divisors is an integer number (67213152).

Almost surely, 2^1243120155 is an apocalyptic number.

1243120155 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1243120155 is a deficient number, since it is larger than the sum of its proper divisors (907700709).

1243120155 is a wasteful number, since it uses less digits than its factorization.

1243120155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103795.

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 1243120155 is about 35257.9091127083. The cubic root of 1243120155 is about 1075.2374179058.

Adding to 1243120155 its reverse (5510213421), we get a palindrome (6753333576).

The spelling of 1243120155 in words is "one billion, two hundred forty-three million, one hundred twenty thousand, one hundred fifty-five".