1620344555 has 4 divisors (see below), whose sum is σ = 1944413472. Its totient is φ = 1296275640.

The previous prime is 1620344543. The next prime is 1620344563. The reversal of 1620344555 is 5554430261.

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

It is not a de Polignac number, because 1620344555 - 2¹⁸ = 1620082411 is a prime.

It is a Duffinian number.

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 3 ways as a sum of consecutive naturals, for example, 162034451 + ... + 162034460.

It is an arithmetic number, because the mean of its divisors is an integer number (486103368).

Almost surely, 2^1620344555 is an apocalyptic number.

1620344555 is a deficient number, since it is larger than the sum of its proper divisors (324068917).

1620344555 is an equidigital number, since it uses as much as digits as its factorization.

1620344555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 324068916.

The product of its (nonzero) digits is 72000, while the sum is 35.

The square root of 1620344555 is about 40253.5036363296. The cubic root of 1620344555 is about 1174.5435510914.

The spelling of 1620344555 in words is "one billion, six hundred twenty million, three hundred forty-four thousand, five hundred fifty-five".