766888721 has 2 divisors, whose sum is σ = 766888722. Its totient is φ = 766888720.

The previous prime is 766888643. The next prime is 766888753. The reversal of 766888721 is 127888667.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 763140625 + 3748096 = 27625^2 + 1936^2 .

It is a cyclic number.

It is not a de Polignac number, because 766888721 - 2²² = 762694417 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (766888021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 383444360 + 383444361.

It is an arithmetic number, because the mean of its divisors is an integer number (383444361).

Almost surely, 2^766888721 is an apocalyptic number.

It is an amenable number.

766888721 is a deficient number, since it is larger than the sum of its proper divisors (1).

766888721 is an equidigital number, since it uses as much as digits as its factorization.

766888721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1806336, while the sum is 53.

The square root of 766888721 is about 27692.7557494735. The cubic root of 766888721 is about 915.3294805156.

The spelling of 766888721 in words is "seven hundred sixty-six million, eight hundred eighty-eight thousand, seven hundred twenty-one".