77806321 has 2 divisors, whose sum is σ = 77806322. Its totient is φ = 77806320.

The previous prime is 77806277. The next prime is 77806327. The reversal of 77806321 is 12360877.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 55338721 + 22467600 = 7439^2 + 4740^2 .

It is an emirp because it is prime and its reverse (12360877) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 77806321 - 2⁷ = 77806193 is a prime.

It is not a weakly prime, because it can be changed into another prime (77806327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 38903160 + 38903161.

It is an arithmetic number, because the mean of its divisors is an integer number (38903161).

Almost surely, 2^77806321 is an apocalyptic number.

It is an amenable number.

77806321 is a deficient number, since it is larger than the sum of its proper divisors (1).

77806321 is an equidigital number, since it uses as much as digits as its factorization.

77806321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14112, while the sum is 34.

The square root of 77806321 is about 8820.7891370330. The cubic root of 77806321 is about 426.9119322129.

The spelling of 77806321 in words is "seventy-seven million, eight hundred six thousand, three hundred twenty-one".