77328781 has 2 divisors, whose sum is σ = 77328782. Its totient is φ = 77328780.

The previous prime is 77328773. The next prime is 77328791. The reversal of 77328781 is 18782377.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72080100 + 5248681 = 8490^2 + 2291^2 .

It is an emirp because it is prime and its reverse (18782377) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77328781 - 2³ = 77328773 is a prime.

It is a super-2 number, since 2×77328781² = 11959480741891922, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (77328791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38664390 + 38664391.

It is an arithmetic number, because the mean of its divisors is an integer number (38664391).

Almost surely, 2^77328781 is an apocalyptic number.

It is an amenable number.

77328781 is a deficient number, since it is larger than the sum of its proper divisors (1).

77328781 is an equidigital number, since it uses as much as digits as its factorization.

77328781 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 131712, while the sum is 43.

The square root of 77328781 is about 8793.6784680815. The cubic root of 77328781 is about 426.0367418184.

The spelling of 77328781 in words is "seventy-seven million, three hundred twenty-eight thousand, seven hundred eighty-one".