7978642447 has 2 divisors, whose sum is σ = 7978642448. Its totient is φ = 7978642446.

The previous prime is 7978642421. The next prime is 7978642457. The reversal of 7978642447 is 7442468797.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 7978642447 - 2⁷ = 7978642319 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 7978642391 and 7978642400.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (7978642457) 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, 3989321223 + 3989321224.

It is an arithmetic number, because the mean of its divisors is an integer number (3989321224).

Almost surely, 2^7978642447 is an apocalyptic number.

7978642447 is a deficient number, since it is larger than the sum of its proper divisors (1).

7978642447 is an equidigital number, since it uses as much as digits as its factorization.

7978642447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18966528, while the sum is 58.

The square root of 7978642447 is about 89323.2469573291. The cubic root of 7978642447 is about 1998.2186177263.

The spelling of 7978642447 in words is "seven billion, nine hundred seventy-eight million, six hundred forty-two thousand, four hundred forty-seven".