77818321 has 12 divisors (see below), whose sum is σ = 90668532. Its totient is φ = 66594528.

The previous prime is 77818297. The next prime is 77818331. The reversal of 77818321 is 12381877.

It can be written as a sum of positive squares in 2 ways, for example, as 76317696 + 1500625 = 8736^2 + 1225^2 .

It is not a de Polignac number, because 77818321 - 2⁷ = 77818193 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77818331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 52831 + ... + 54283.

It is an arithmetic number, because the mean of its divisors is an integer number (7555711).

Almost surely, 2^77818321 is an apocalyptic number.

It is an amenable number.

77818321 is a deficient number, since it is larger than the sum of its proper divisors (12850211).

77818321 is a wasteful number, since it uses less digits than its factorization.

77818321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2560 (or 2553 counting only the distinct ones).

The product of its digits is 18816, while the sum is 37.

The square root of 77818321 is about 8821.4693220574. The cubic root of 77818321 is about 426.9338785011.

The spelling of 77818321 in words is "seventy-seven million, eight hundred eighteen thousand, three hundred twenty-one".