1205120551 has 4 divisors (see below), whose sum is σ = 1205546104. Its totient is φ = 1204695000.

The previous prime is 1205120513. The next prime is 1205120569. The reversal of 1205120551 is 1550215021.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1205120551 - 2¹¹ = 1205118503 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 (1205120591) 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, 208500 + ... + 214201.

It is an arithmetic number, because the mean of its divisors is an integer number (301386526).

Almost surely, 2^1205120551 is an apocalyptic number.

1205120551 is a deficient number, since it is larger than the sum of its proper divisors (425553).

1205120551 is an equidigital number, since it uses as much as digits as its factorization.

1205120551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425552.

The product of its (nonzero) digits is 500, while the sum is 22.

The square root of 1205120551 is about 34714.8462620822. The cubic root of 1205120551 is about 1064.1679236231.

Adding to 1205120551 its reverse (1550215021), we get a palindrome (2755335572).

The spelling of 1205120551 in words is "one billion, two hundred five million, one hundred twenty thousand, five hundred fifty-one".