1605666564 has 30 divisors (see below), whose sum is σ = 4197530414. Its totient is φ = 535222080.

The previous prime is 1605666563. The next prime is 1605666571. The reversal of 1605666564 is 4656665061.

It can be written as a sum of positive squares in only one way, i.e., 1368260100 + 237406464 = 36990^2 + 15408^2 .

It is a super-2 number, since 2×1605666564² = 5156330229495132192, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1605666563) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 2477557 + ... + 2478204.

Almost surely, 2^1605666564 is an apocalyptic number.

It is an amenable number.

1605666564 is an abundant number, since it is smaller than the sum of its proper divisors (2591863850).

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

1605666564 is a wasteful number, since it uses less digits than its factorization.

1605666564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4955777 (or 4955766 counting only the distinct ones).

The product of its (nonzero) digits is 777600, while the sum is 45.

The square root of 1605666564 is about 40070.7694460688. The cubic root of 1605666564 is about 1170.9862295866.

The spelling of 1605666564 in words is "one billion, six hundred five million, six hundred sixty-six thousand, five hundred sixty-four".