78987641 has 2 divisors, whose sum is σ = 78987642. Its totient is φ = 78987640.

The previous prime is 78987611. The next prime is 78987653. The reversal of 78987641 is 14678987.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 75620416 + 3367225 = 8696^2 + 1835^2 .

It is a cyclic number.

It is not a de Polignac number, because 78987641 - 2⁶ = 78987577 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 78987641.

It is not a weakly prime, because it can be changed into another prime (78987611) 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, 39493820 + 39493821.

It is an arithmetic number, because the mean of its divisors is an integer number (39493821).

Almost surely, 2^78987641 is an apocalyptic number.

It is an amenable number.

78987641 is a deficient number, since it is larger than the sum of its proper divisors (1).

78987641 is an equidigital number, since it uses as much as digits as its factorization.

78987641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 677376, while the sum is 50.

The square root of 78987641 is about 8887.4991420534. The cubic root of 78987641 is about 429.0616657986.

The spelling of 78987641 in words is "seventy-eight million, nine hundred eighty-seven thousand, six hundred forty-one".