78648367621 has 2 divisors, whose sum is σ = 78648367622. Its totient is φ = 78648367620.

The previous prime is 78648367601. The next prime is 78648367643. The reversal of 78648367621 is 12676384687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77498208225 + 1150159396 = 278385^2 + 33914^2 .

It is an emirp because it is prime and its reverse (12676384687) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 78648367621 - 2¹⁹ = 78647843333 is a prime.

It is a super-2 number, since 2×78648367621² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78648367601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39324183810 + 39324183811.

It is an arithmetic number, because the mean of its divisors is an integer number (39324183811).

Almost surely, 2^78648367621 is an apocalyptic number.

It is an amenable number.

78648367621 is a deficient number, since it is larger than the sum of its proper divisors (1).

78648367621 is an equidigital number, since it uses as much as digits as its factorization.

78648367621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 16257024, while the sum is 58.

The spelling of 78648367621 in words is "seventy-eight billion, six hundred forty-eight million, three hundred sixty-seven thousand, six hundred twenty-one".