77680840381 has 2 divisors, whose sum is σ = 77680840382. Its totient is φ = 77680840380.

The previous prime is 77680840379. The next prime is 77680840403. The reversal of 77680840381 is 18304808677.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 68047417881 + 9633422500 = 260859^2 + 98150^2 .

It is a cyclic number.

It is not a de Polignac number, because 77680840381 - 2¹ = 77680840379 is a prime.

It is a super-2 number, since 2×77680840381² (a number of 23 digits) contains 22 as substring.

Together with 77680840379, 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 (77680840351) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38840420190 + 38840420191.

It is an arithmetic number, because the mean of its divisors is an integer number (38840420191).

Almost surely, 2^77680840381 is an apocalyptic number.

It is an amenable number.

77680840381 is a deficient number, since it is larger than the sum of its proper divisors (1).

77680840381 is an equidigital number, since it uses as much as digits as its factorization.

77680840381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1806336, while the sum is 52.

The spelling of 77680840381 in words is "seventy-seven billion, six hundred eighty million, eight hundred forty thousand, three hundred eighty-one".