77978897 has 2 divisors, whose sum is σ = 77978898. Its totient is φ = 77978896.

The previous prime is 77978839. The next prime is 77978933. The reversal of 77978897 is 79887977.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51394561 + 26584336 = 7169^2 + 5156^2 .

It is a cyclic number.

It is not a de Polignac number, because 77978897 - 2¹⁴ = 77962513 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (77978807) 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 as a sum of consecutive naturals, namely, 38989448 + 38989449.

It is an arithmetic number, because the mean of its divisors is an integer number (38989449).

Almost surely, 2^77978897 is an apocalyptic number.

It is an amenable number.

77978897 is a deficient number, since it is larger than the sum of its proper divisors (1).

77978897 is an equidigital number, since it uses as much as digits as its factorization.

77978897 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12446784, while the sum is 62.

The square root of 77978897 is about 8830.5660633959. The cubic root of 77978897 is about 427.2273322515.

The spelling of 77978897 in words is "seventy-seven million, nine hundred seventy-eight thousand, eight hundred ninety-seven".