1989764993 has 2 divisors, whose sum is σ = 1989764994. Its totient is φ = 1989764992.

The previous prime is 1989764963. The next prime is 1989765013. The reversal of 1989764993 is 3994679891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1564044304 + 425720689 = 39548^2 + 20633^2 .

It is an emirp because it is prime and its reverse (3994679891) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1989764993 - 2¹⁸ = 1989502849 is a prime.

It is not a weakly prime, because it can be changed into another prime (1989764963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994882496 + 994882497.

It is an arithmetic number, because the mean of its divisors is an integer number (994882497).

Almost surely, 2^1989764993 is an apocalyptic number.

It is an amenable number.

1989764993 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989764993 is an equidigital number, since it uses as much as digits as its factorization.

1989764993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26453952, while the sum is 65.

The square root of 1989764993 is about 44606.7819171031. The cubic root of 1989764993 is about 1257.7681564336.

The spelling of 1989764993 in words is "one billion, nine hundred eighty-nine million, seven hundred sixty-four thousand, nine hundred ninety-three".