766065721 has 2 divisors, whose sum is σ = 766065722. Its totient is φ = 766065720.

The previous prime is 766065719. The next prime is 766065767. The reversal of 766065721 is 127560667.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 631969321 + 134096400 = 25139^2 + 11580^2 .

It is a cyclic number.

It is not a de Polignac number, because 766065721 - 2¹ = 766065719 is a prime.

Together with 766065719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (766065701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 383032860 + 383032861.

It is an arithmetic number, because the mean of its divisors is an integer number (383032861).

Almost surely, 2^766065721 is an apocalyptic number.

It is an amenable number.

766065721 is a deficient number, since it is larger than the sum of its proper divisors (1).

766065721 is an equidigital number, since it uses as much as digits as its factorization.

766065721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 105840, while the sum is 40.

The square root of 766065721 is about 27677.8922788568. The cubic root of 766065721 is about 915.0019293857.

The spelling of 766065721 in words is "seven hundred sixty-six million, sixty-five thousand, seven hundred twenty-one".