7857381979 has 2 divisors, whose sum is σ = 7857381980. Its totient is φ = 7857381978.

The previous prime is 7857381977. The next prime is 7857382009. The reversal of 7857381979 is 9791837587.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 7857381979 - 2¹ = 7857381977 is a prime.

Together with 7857381977, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 7857381979.

It is not a weakly prime, because it can be changed into another prime (7857381971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3928690989 + 3928690990.

It is an arithmetic number, because the mean of its divisors is an integer number (3928690990).

Almost surely, 2^7857381979 is an apocalyptic number.

7857381979 is a deficient number, since it is larger than the sum of its proper divisors (1).

7857381979 is an equidigital number, since it uses as much as digits as its factorization.

7857381979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 26671680, while the sum is 64.

The square root of 7857381979 is about 88641.8748617153. The cubic root of 7857381979 is about 1988.0438323723.

The spelling of 7857381979 in words is "seven billion, eight hundred fifty-seven million, three hundred eighty-one thousand, nine hundred seventy-nine".