76812781 has 2 divisors, whose sum is σ = 76812782. Its totient is φ = 76812780.

The previous prime is 76812779. The next prime is 76812797. The reversal of 76812781 is 18721867.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72675625 + 4137156 = 8525^2 + 2034^2 .

It is an emirp because it is prime and its reverse (18721867) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 76812781 - 2¹ = 76812779 is a prime.

It is a super-2 number, since 2×76812781² = 11800406649907922, which contains 22 as substring.

Together with 76812779, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (76812731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38406390 + 38406391.

It is an arithmetic number, because the mean of its divisors is an integer number (38406391).

Almost surely, 2^76812781 is an apocalyptic number.

It is an amenable number.

76812781 is a deficient number, since it is larger than the sum of its proper divisors (1).

76812781 is an equidigital number, since it uses as much as digits as its factorization.

76812781 is an evil number, because the sum of its binary digits is even.

The product of its digits is 37632, while the sum is 40.

The square root of 76812781 is about 8764.2901024555. The cubic root of 76812781 is about 425.0870059470.

The spelling of 76812781 in words is "seventy-six million, eight hundred twelve thousand, seven hundred eighty-one".