1989397765 has 8 divisors (see below), whose sum is σ = 2491072128. Its totient is φ = 1522321680.

The previous prime is 1989397763. The next prime is 1989397789. The reversal of 1989397765 is 5677939891.

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

It is not a de Polignac number, because 1989397765 - 2¹ = 1989397763 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1989397697 and 1989397706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1989397763) 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, 8649441 + ... + 8649670.

It is an arithmetic number, because the mean of its divisors is an integer number (311384016).

Almost surely, 2^1989397765 is an apocalyptic number.

It is an amenable number.

1989397765 is a deficient number, since it is larger than the sum of its proper divisors (501674363).

1989397765 is a wasteful number, since it uses less digits than its factorization.

1989397765 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17299139.

The product of its digits is 25719120, while the sum is 64.

The square root of 1989397765 is about 44602.6654472577. The cubic root of 1989397765 is about 1257.6907744137.

The spelling of 1989397765 in words is "one billion, nine hundred eighty-nine million, three hundred ninety-seven thousand, seven hundred sixty-five".