766745981 has 2 divisors, whose sum is σ = 766745982. Its totient is φ = 766745980.

The previous prime is 766745953. The next prime is 766746031. The reversal of 766745981 is 189547667.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 735765625 + 30980356 = 27125^2 + 5566^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-766745981 is a prime.

It is a super-2 number, since 2×766745981² = 1175798798759304722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (766745911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 383372990 + 383372991.

It is an arithmetic number, because the mean of its divisors is an integer number (383372991).

Almost surely, 2^766745981 is an apocalyptic number.

It is an amenable number.

766745981 is a deficient number, since it is larger than the sum of its proper divisors (1).

766745981 is an equidigital number, since it uses as much as digits as its factorization.

766745981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2540160, while the sum is 53.

The square root of 766745981 is about 27690.1784212381. The cubic root of 766745981 is about 915.2726872967.

The spelling of 766745981 in words is "seven hundred sixty-six million, seven hundred forty-five thousand, nine hundred eighty-one".