78280620166621 has 2 divisors, whose sum is σ = 78280620166622. Its totient is φ = 78280620166620.

The previous prime is 78280620166579. The next prime is 78280620166643. The reversal of 78280620166621 is 12666102608287.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 76875895052100 + 1404725114521 = 8767890^2 + 1185211^2 .

It is a cyclic number.

It is not a de Polignac number, because 78280620166621 - 2²¹ = 78280618069469 is a prime.

It is a super-2 number, since 2×78280620166621² (a number of 29 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78280620163621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39140310083310 + 39140310083311.

It is an arithmetic number, because the mean of its divisors is an integer number (39140310083311).

Almost surely, 2^{78280620166621} is an apocalyptic number.

It is an amenable number.

78280620166621 is a deficient number, since it is larger than the sum of its proper divisors (1).

78280620166621 is an equidigital number, since it uses as much as digits as its factorization.

78280620166621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4644864, while the sum is 55.

The spelling of 78280620166621 in words is "seventy-eight trillion, two hundred eighty billion, six hundred twenty million, one hundred sixty-six thousand, six hundred twenty-one".