78155455186 has 4 divisors (see below), whose sum is σ = 117233182782. Its totient is φ = 39077727592.

The previous prime is 78155455127. The next prime is 78155455207. The reversal of 78155455186 is 68155455187.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 68155455187 = 101 ⋅674806487.

It can be written as a sum of positive squares in only one way, i.e., 74777637025 + 3377818161 = 273455^2 + 58119^2 .

It is a super-2 number, since 2×78155455186² (a number of 23 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19538863795 + ... + 19538863798.

Almost surely, 2^78155455186 is an apocalyptic number.

78155455186 is a deficient number, since it is larger than the sum of its proper divisors (39077727596).

78155455186 is a wasteful number, since it uses less digits than its factorization.

78155455186 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39077727595.

The product of its digits is 6720000, while the sum is 55.

Subtracting from 78155455186 its reverse (68155455187), we obtain a palindrome (9999999999).

The spelling of 78155455186 in words is "seventy-eight billion, one hundred fifty-five million, four hundred fifty-five thousand, one hundred eighty-six".