78332561 has 2 divisors, whose sum is σ = 78332562. Its totient is φ = 78332560.

The previous prime is 78332557. The next prime is 78332563. The reversal of 78332561 is 16523387.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52128400 + 26204161 = 7220^2 + 5119^2 .

It is a cyclic number.

It is not a de Polignac number, because 78332561 - 2² = 78332557 is a prime.

It is a super-2 number, since 2×78332561² = 12271980225637442, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 78332563, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (78332563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39166280 + 39166281.

It is an arithmetic number, because the mean of its divisors is an integer number (39166281).

Almost surely, 2^78332561 is an apocalyptic number.

It is an amenable number.

78332561 is a deficient number, since it is larger than the sum of its proper divisors (1).

78332561 is an equidigital number, since it uses as much as digits as its factorization.

78332561 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 30240, while the sum is 35.

The square root of 78332561 is about 8850.5683998261. The cubic root of 78332561 is about 427.8722378285.

The spelling of 78332561 in words is "seventy-eight million, three hundred thirty-two thousand, five hundred sixty-one".