7978849 has 2 divisors, whose sum is σ = 7978850. Its totient is φ = 7978848.

The previous prime is 7978847. The next prime is 7978871. The reversal of 7978849 is 9488797.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6838225 + 1140624 = 2615^2 + 1068^2 .

It is an emirp because it is prime and its reverse (9488797) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 7978849 - 2¹ = 7978847 is a prime.

Together with 7978847, it forms a pair of twin primes.

It is an Ulam number.

It is a junction number, because it is equal to n+sod(n) for n = 7978796 and 7978805.

It is not a weakly prime, because it can be changed into another prime (7978847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3989424 + 3989425.

It is an arithmetic number, because the mean of its divisors is an integer number (3989425).

Almost surely, 2^7978849 is an apocalyptic number.

It is an amenable number.

7978849 is a deficient number, since it is larger than the sum of its proper divisors (1).

7978849 is an equidigital number, since it uses as much as digits as its factorization.

7978849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1016064, while the sum is 52.

The square root of 7978849 is about 2824.6856462269. The cubic root of 7978849 is about 199.8235861031.

Subtracting from 7978849 its sum of digits (52), we obtain a palindrome (7978797).

The spelling of 7978849 in words is "seven million, nine hundred seventy-eight thousand, eight hundred forty-nine".