77606456981 has 2 divisors, whose sum is σ = 77606456982. Its totient is φ = 77606456980.

The previous prime is 77606456953. The next prime is 77606457013. The reversal of 77606456981 is 18965460677.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72474024100 + 5132432881 = 269210^2 + 71641^2 .

It is an emirp because it is prime and its reverse (18965460677) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77606456981 - 2¹⁰ = 77606455957 is a prime.

It is a super-2 number, since 2×77606456981² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 77606456981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77606456911) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38803228490 + 38803228491.

It is an arithmetic number, because the mean of its divisors is an integer number (38803228491).

Almost surely, 2^77606456981 is an apocalyptic number.

It is an amenable number.

77606456981 is a deficient number, since it is larger than the sum of its proper divisors (1).

77606456981 is an equidigital number, since it uses as much as digits as its factorization.

77606456981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15240960, while the sum is 59.

The spelling of 77606456981 in words is "seventy-seven billion, six hundred six million, four hundred fifty-six thousand, nine hundred eighty-one".