1665797987 has 8 divisors (see below), whose sum is σ = 1904386656. Its totient is φ = 1427363712.

The previous prime is 1665797899. The next prime is 1665797999. The reversal of 1665797987 is 7897975661.

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

It is a cyclic number.

It is not a de Polignac number, because 1665797987 - 2¹⁰ = 1665796963 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1665797087) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14468 + ... + 59505.

It is an arithmetic number, because the mean of its divisors is an integer number (238048332).

Almost surely, 2^1665797987 is an apocalyptic number.

1665797987 is a deficient number, since it is larger than the sum of its proper divisors (238588669).

1665797987 is an equidigital number, since it uses as much as digits as its factorization.

1665797987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77197.

The product of its digits is 40007520, while the sum is 65.

The square root of 1665797987 is about 40814.1885500619. The cubic root of 1665797987 is about 1185.4250789730.

The spelling of 1665797987 in words is "one billion, six hundred sixty-five million, seven hundred ninety-seven thousand, nine hundred eighty-seven".