77766641 has 2 divisors, whose sum is σ = 77766642. Its totient is φ = 77766640.

The previous prime is 77766629. The next prime is 77766673. The reversal of 77766641 is 14666777.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75620416 + 2146225 = 8696^2 + 1465^2 .

It is an emirp because it is prime and its reverse (14666777) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77766641 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 77766592 and 77766601.

It is not a weakly prime, because it can be changed into another prime (77766541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38883320 + 38883321.

It is an arithmetic number, because the mean of its divisors is an integer number (38883321).

Almost surely, 2^77766641 is an apocalyptic number.

It is an amenable number.

77766641 is a deficient number, since it is larger than the sum of its proper divisors (1).

77766641 is an equidigital number, since it uses as much as digits as its factorization.

77766641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 296352, while the sum is 44.

The square root of 77766641 is about 8818.5396183268. The cubic root of 77766641 is about 426.8393470820.

The spelling of 77766641 in words is "seventy-seven million, seven hundred sixty-six thousand, six hundred forty-one".