1121256165 has 16 divisors (see below), whose sum is σ = 1899540288. Its totient is φ = 562826496.

The previous prime is 1121256161. The next prime is 1121256167. The reversal of 1121256165 is 5616521211.

It is not a de Polignac number, because 1121256165 - 2² = 1121256161 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1121256161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2198287 + ... + 2198796.

It is an arithmetic number, because the mean of its divisors is an integer number (118721268).

Almost surely, 2^1121256165 is an apocalyptic number.

1121256165 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1121256165 is a deficient number, since it is larger than the sum of its proper divisors (778284123).

1121256165 is a wasteful number, since it uses less digits than its factorization.

1121256165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4397108.

The product of its digits is 3600, while the sum is 30.

The square root of 1121256165 is about 33485.1633563284. The cubic root of 1121256165 is about 1038.8869270566.

Adding to 1121256165 its reverse (5616521211), we get a palindrome (6737777376).

The spelling of 1121256165 in words is "one billion, one hundred twenty-one million, two hundred fifty-six thousand, one hundred sixty-five".