1997806565 has 8 divisors (see below), whose sum is σ = 2501601408. Its totient is φ = 1528756240.

The previous prime is 1997806537. The next prime is 1997806579. The reversal of 1997806565 is 5656087991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-1997806565 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1997806565.

It is a congruent 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 7 ways as a sum of consecutive naturals, for example, 8686001 + ... + 8686230.

It is an arithmetic number, because the mean of its divisors is an integer number (312700176).

Almost surely, 2^1997806565 is an apocalyptic number.

It is an amenable number.

1997806565 is a deficient number, since it is larger than the sum of its proper divisors (503794843).

1997806565 is a wasteful number, since it uses less digits than its factorization.

1997806565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17372259.

The product of its (nonzero) digits is 4082400, while the sum is 56.

The square root of 1997806565 is about 44696.8294736886. The cubic root of 1997806565 is about 1259.4602889242.

The spelling of 1997806565 in words is "one billion, nine hundred ninety-seven million, eight hundred six thousand, five hundred sixty-five".