1600661565 has 24 divisors (see below), whose sum is σ = 2778631128. Its totient is φ = 852408960.

The previous prime is 1600661549. The next prime is 1600661591. The reversal of 1600661565 is 5651660061.

1600661565 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 1169434809 + 431226756 = 34197^2 + 20766^2 .

It is not a de Polignac number, because 1600661565 - 2⁴ = 1600661549 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4195 + ... + 56735.

It is an arithmetic number, because the mean of its divisors is an integer number (115776297).

Almost surely, 2^1600661565 is an apocalyptic number.

1600661565 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1600661565 is a deficient number, since it is larger than the sum of its proper divisors (1177969563).

1600661565 is a wasteful number, since it uses less digits than its factorization.

1600661565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53229 (or 53226 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 1600661565 is about 40008.2687078559. The cubic root of 1600661565 is about 1169.7682753886.

The spelling of 1600661565 in words is "one billion, six hundred million, six hundred sixty-one thousand, five hundred sixty-five".