78820111 has 2 divisors, whose sum is σ = 78820112. Its totient is φ = 78820110.

The previous prime is 78820087. The next prime is 78820121. The reversal of 78820111 is 11102887.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 78820111 - 2¹³ = 78811919 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78820111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78820121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39410055 + 39410056.

It is an arithmetic number, because the mean of its divisors is an integer number (39410056).

Almost surely, 2^78820111 is an apocalyptic number.

78820111 is a deficient number, since it is larger than the sum of its proper divisors (1).

78820111 is an equidigital number, since it uses as much as digits as its factorization.

78820111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 896, while the sum is 28.

The square root of 78820111 is about 8878.0691031327. The cubic root of 78820111 is about 428.7581095345.

Adding to 78820111 its reverse (11102887), we get a palindrome (89922998).

The spelling of 78820111 in words is "seventy-eight million, eight hundred twenty thousand, one hundred eleven".