78041687621 has 2 divisors, whose sum is σ = 78041687622. Its totient is φ = 78041687620.

The previous prime is 78041687587. The next prime is 78041687623. The reversal of 78041687621 is 12678614087.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70113744100 + 7927943521 = 264790^2 + 89039^2 .

It is a cyclic number.

It is not a de Polignac number, because 78041687621 - 2⁶ = 78041687557 is a prime.

Together with 78041687623, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78041687621.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78041687623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39020843810 + 39020843811.

It is an arithmetic number, because the mean of its divisors is an integer number (39020843811).

Almost surely, 2^78041687621 is an apocalyptic number.

It is an amenable number.

78041687621 is a deficient number, since it is larger than the sum of its proper divisors (1).

78041687621 is an equidigital number, since it uses as much as digits as its factorization.

78041687621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 903168, while the sum is 50.

The spelling of 78041687621 in words is "seventy-eight billion, forty-one million, six hundred eighty-seven thousand, six hundred twenty-one".