1620205566 has 32 divisors (see below), whose sum is σ = 3730371840. Its totient is φ = 459535296.

The previous prime is 1620205529. The next prime is 1620205571. The reversal of 1620205566 is 6655020261.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 135036 + ... + 146543.

It is an arithmetic number, because the mean of its divisors is an integer number (116574120).

Almost surely, 2^1620205566 is an apocalyptic number.

1620205566 is an abundant number, since it is smaller than the sum of its proper divisors (2110166274).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1620205566 is a wasteful number, since it uses less digits than its factorization.

1620205566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281728.

The product of its (nonzero) digits is 21600, while the sum is 33.

The square root of 1620205566 is about 40251.7771781570. Note that the first 3 decimals coincide. The cubic root of 1620205566 is about 1174.5099670201.

The spelling of 1620205566 in words is "one billion, six hundred twenty million, two hundred five thousand, five hundred sixty-six".