1620440660 has 12 divisors (see below), whose sum is σ = 3402925428. Its totient is φ = 648176256.

The previous prime is 1620440659. The next prime is 1620440671. The reversal of 1620440660 is 660440261.

It can be written as a sum of positive squares in 2 ways, for example, as 601426576 + 1019014084 = 24524^2 + 31922^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 40510997 + ... + 40511036.

It is an arithmetic number, because the mean of its divisors is an integer number (283577119).

Almost surely, 2^1620440660 is an apocalyptic number.

1620440660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1620440660 is an abundant number, since it is smaller than the sum of its proper divisors (1782484768).

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

1620440660 is a wasteful number, since it uses less digits than its factorization.

1620440660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81022042 (or 81022040 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 29.

The square root of 1620440660 is about 40254.6973656491. The cubic root of 1620440660 is about 1174.5667719297.

The spelling of 1620440660 in words is "one billion, six hundred twenty million, four hundred forty thousand, six hundred sixty".