1205123555 has 8 divisors (see below), whose sum is σ = 1450770432. Its totient is φ = 961017408.

The previous prime is 1205123533. The next prime is 1205123581. The reversal of 1205123555 is 5553215021.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1205123555 - 2¹⁰ = 1205122531 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 383459 + ... + 386588.

It is an arithmetic number, because the mean of its divisors is an integer number (181346304).

Almost surely, 2^1205123555 is an apocalyptic number.

1205123555 is a deficient number, since it is larger than the sum of its proper divisors (245646877).

1205123555 is an equidigital number, since it uses as much as digits as its factorization.

1205123555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 770365.

The product of its (nonzero) digits is 7500, while the sum is 29.

The square root of 1205123555 is about 34714.8895288463. The cubic root of 1205123555 is about 1064.1688078383.

Adding to 1205123555 its reverse (5553215021), we get a palindrome (6758338576).

The spelling of 1205123555 in words is "one billion, two hundred five million, one hundred twenty-three thousand, five hundred fifty-five".