78155557111 has 2 divisors, whose sum is σ = 78155557112. Its totient is φ = 78155557110.

The previous prime is 78155557099. The next prime is 78155557127. The reversal of 78155557111 is 11175555187.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78155557111 - 2⁵ = 78155557079 is a prime.

It is a super-2 number, since 2×78155557111² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78155557411) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39077778555 + 39077778556.

It is an arithmetic number, because the mean of its divisors is an integer number (39077778556).

Almost surely, 2^78155557111 is an apocalyptic number.

78155557111 is a deficient number, since it is larger than the sum of its proper divisors (1).

78155557111 is an equidigital number, since it uses as much as digits as its factorization.

78155557111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 245000, while the sum is 46.

The spelling of 78155557111 in words is "seventy-eight billion, one hundred fifty-five million, five hundred fifty-seven thousand, one hundred eleven".