7858138388521 has 2 divisors, whose sum is σ = 7858138388522. Its totient is φ = 7858138388520.

The previous prime is 7858138388501. The next prime is 7858138388539. The reversal of 7858138388521 is 1258838318587.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7649096490000 + 209041898521 = 2765700^2 + 457211^2 .

It is a cyclic number.

It is not a de Polignac number, because 7858138388521 - 2⁷ = 7858138388393 is a prime.

It is not a weakly prime, because it can be changed into another prime (7858138388501) 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, 3929069194260 + 3929069194261.

It is an arithmetic number, because the mean of its divisors is an integer number (3929069194261).

Almost surely, 2^{7858138388521} is an apocalyptic number.

It is an amenable number.

7858138388521 is a deficient number, since it is larger than the sum of its proper divisors (1).

7858138388521 is an equidigital number, since it uses as much as digits as its factorization.

7858138388521 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 103219200, while the sum is 67.

The spelling of 7858138388521 in words is "seven trillion, eight hundred fifty-eight billion, one hundred thirty-eight million, three hundred eighty-eight thousand, five hundred twenty-one".