77682821 has 2 divisors, whose sum is σ = 77682822. Its totient is φ = 77682820.

The previous prime is 77682769. The next prime is 77682827. The reversal of 77682821 is 12828677.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 47761921 + 29920900 = 6911^2 + 5470^2 .

It is a cyclic number.

It is not a de Polignac number, because 77682821 - 2¹⁸ = 77420677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77682827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38841410 + 38841411.

It is an arithmetic number, because the mean of its divisors is an integer number (38841411).

Almost surely, 2^77682821 is an apocalyptic number.

It is an amenable number.

77682821 is a deficient number, since it is larger than the sum of its proper divisors (1).

77682821 is an equidigital number, since it uses as much as digits as its factorization.

77682821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 75264, while the sum is 41.

The square root of 77682821 is about 8813.7858494520. The cubic root of 77682821 is about 426.6859371044.

The spelling of 77682821 in words is "seventy-seven million, six hundred eighty-two thousand, eight hundred twenty-one".