78056621 has 2 divisors, whose sum is σ = 78056622. Its totient is φ = 78056620.

The previous prime is 78056611. The next prime is 78056623. The reversal of 78056621 is 12665087.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76650025 + 1406596 = 8755^2 + 1186^2 .

It is an emirp because it is prime and its reverse (12665087) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78056621 - 2⁶ = 78056557 is a prime.

Together with 78056623, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78056623) 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, 39028310 + 39028311.

It is an arithmetic number, because the mean of its divisors is an integer number (39028311).

Almost surely, 2^78056621 is an apocalyptic number.

It is an amenable number.

78056621 is a deficient number, since it is larger than the sum of its proper divisors (1).

78056621 is an equidigital number, since it uses as much as digits as its factorization.

78056621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 20160, while the sum is 35.

The square root of 78056621 is about 8834.9658177041. The cubic root of 78056621 is about 427.3692287223.

The spelling of 78056621 in words is "seventy-eight million, fifty-six thousand, six hundred twenty-one".