1213120155 has 32 divisors (see below), whose sum is σ = 2091995136. Its totient is φ = 596744064.

The previous prime is 1213120123. The next prime is 1213120159. The reversal of 1213120155 is 5510213121.

It is not a de Polignac number, because 1213120155 - 2⁵ = 1213120123 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1213120159) 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 31 ways as a sum of consecutive naturals, for example, 416434 + ... + 419336.

It is an arithmetic number, because the mean of its divisors is an integer number (65374848).

Almost surely, 2^1213120155 is an apocalyptic number.

1213120155 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1213120155 is a deficient number, since it is larger than the sum of its proper divisors (878874981).

1213120155 is a wasteful number, since it uses less digits than its factorization.

1213120155 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5067.

The product of its (nonzero) digits is 300, while the sum is 21.

The square root of 1213120155 is about 34829.8744614447. The cubic root of 1213120155 is about 1066.5173856302.

Adding to 1213120155 its reverse (5510213121), we get a palindrome (6723333276).

The spelling of 1213120155 in words is "one billion, two hundred thirteen million, one hundred twenty thousand, one hundred fifty-five".