1620565555 has 16 divisors (see below), whose sum is σ = 2238485760. Its totient is φ = 1103247072.

The previous prime is 1620565547. The next prime is 1620565591. The reversal of 1620565555 is 5555650261.

It is a cyclic number.

It is not a de Polignac number, because 1620565555 - 2³ = 1620565547 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 15 ways as a sum of consecutive naturals, for example, 161689 + ... + 171418.

It is an arithmetic number, because the mean of its divisors is an integer number (139905360).

Almost surely, 2^1620565555 is an apocalyptic number.

1620565555 is a deficient number, since it is larger than the sum of its proper divisors (617920205).

1620565555 is a wasteful number, since it uses less digits than its factorization.

1620565555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333258.

The product of its (nonzero) digits is 225000, while the sum is 40.

The square root of 1620565555 is about 40256.2486453967. The cubic root of 1620565555 is about 1174.5969476203.

The spelling of 1620565555 in words is "one billion, six hundred twenty million, five hundred sixty-five thousand, five hundred fifty-five".