1320405555 has 32 divisors (see below), whose sum is σ = 2556486144. Its totient is φ = 568106496.

The previous prime is 1320405503. The next prime is 1320405571. The reversal of 1320405555 is 5555040231.

It is a happy number.

It is not a de Polignac number, because 1320405555 - 2⁶ = 1320405491 is a prime.

It is an unprimeable number.

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, 368077 + ... + 371646.

It is an arithmetic number, because the mean of its divisors is an integer number (79890192).

Almost surely, 2^1320405555 is an apocalyptic number.

1320405555 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

1320405555 is a deficient number, since it is larger than the sum of its proper divisors (1236080589).

1320405555 is a wasteful number, since it uses less digits than its factorization.

1320405555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 739755.

The product of its (nonzero) digits is 15000, while the sum is 30.

The square root of 1320405555 is about 36337.3850875376. The cubic root of 1320405555 is about 1097.0736419488.

Adding to 1320405555 its reverse (5555040231), we get a palindrome (6875445786).

The spelling of 1320405555 in words is "one billion, three hundred twenty million, four hundred five thousand, five hundred fifty-five".