766856381 has 2 divisors, whose sum is σ = 766856382. Its totient is φ = 766856380.

The previous prime is 766856351. The next prime is 766856401. The reversal of 766856381 is 183658667.

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., 672105625 + 94750756 = 25925^2 + 9734^2 .

It is a cyclic number.

It is not a de Polignac number, because 766856381 - 2¹⁸ = 766594237 is a prime.

It is a super-2 number, since 2×766856381² = 1176137418160834322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (766856351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 383428190 + 383428191.

It is an arithmetic number, because the mean of its divisors is an integer number (383428191).

Almost surely, 2^766856381 is an apocalyptic number.

It is an amenable number.

766856381 is a deficient number, since it is larger than the sum of its proper divisors (1).

766856381 is an equidigital number, since it uses as much as digits as its factorization.

766856381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1451520, while the sum is 50.

The square root of 766856381 is about 27692.1718360984. The cubic root of 766856381 is about 915.3166137330.

The spelling of 766856381 in words is "seven hundred sixty-six million, eight hundred fifty-six thousand, three hundred eighty-one".