1664736765 has 8 divisors (see below), whose sum is σ = 2663578848. Its totient is φ = 887859600.

The previous prime is 1664736761. The next prime is 1664736791. The reversal of 1664736765 is 5676374661.

It is a happy number.

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

It is not a de Polignac number, because 1664736765 - 2² = 1664736761 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1664736761) 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, 55491211 + ... + 55491240.

It is an arithmetic number, because the mean of its divisors is an integer number (332947356).

Almost surely, 2^1664736765 is an apocalyptic number.

1664736765 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

1664736765 is a deficient number, since it is larger than the sum of its proper divisors (998842083).

1664736765 is a wasteful number, since it uses less digits than its factorization.

1664736765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110982459.

The product of its digits is 3810240, while the sum is 51.

The square root of 1664736765 is about 40801.1858283555. The cubic root of 1664736765 is about 1185.1732944589.

The spelling of 1664736765 in words is "one billion, six hundred sixty-four million, seven hundred thirty-six thousand, seven hundred sixty-five".