78671641 has 2 divisors, whose sum is σ = 78671642. Its totient is φ = 78671640.

The previous prime is 78671629. The next prime is 78671669. The reversal of 78671641 is 14617687.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51423241 + 27248400 = 7171^2 + 5220^2 .

It is a cyclic number.

It is not a de Polignac number, because 78671641 - 2⁹ = 78671129 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 78671594 and 78671603.

It is not a weakly prime, because it can be changed into another prime (78671141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39335820 + 39335821.

It is an arithmetic number, because the mean of its divisors is an integer number (39335821).

Almost surely, 2^78671641 is an apocalyptic number.

It is an amenable number.

78671641 is a deficient number, since it is larger than the sum of its proper divisors (1).

78671641 is an equidigital number, since it uses as much as digits as its factorization.

78671641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 56448, while the sum is 40.

The square root of 78671641 is about 8869.7035463425. The cubic root of 78671641 is about 428.4887293499.

It can be divided in two parts, 786 and 71641, that added together give a palindrome (72427).

The spelling of 78671641 in words is "seventy-eight million, six hundred seventy-one thousand, six hundred forty-one".