766648921 has 2 divisors, whose sum is σ = 766648922. Its totient is φ = 766648920.

The previous prime is 766648919. The next prime is 766648931. The reversal of 766648921 is 129846667.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 434097225 + 332551696 = 20835^2 + 18236^2 .

It is an emirp because it is prime and its reverse (129846667) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 766648921 - 2¹ = 766648919 is a prime.

Together with 766648919, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (766648931) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 383324460 + 383324461.

It is an arithmetic number, because the mean of its divisors is an integer number (383324461).

Almost surely, 2^766648921 is an apocalyptic number.

It is an amenable number.

766648921 is a deficient number, since it is larger than the sum of its proper divisors (1).

766648921 is an equidigital number, since it uses as much as digits as its factorization.

766648921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 870912, while the sum is 49.

The square root of 766648921 is about 27688.4257587895. The cubic root of 766648921 is about 915.2340651550.

The spelling of 766648921 in words is "seven hundred sixty-six million, six hundred forty-eight thousand, nine hundred twenty-one".