78131139 has 4 divisors (see below), whose sum is σ = 104174856. Its totient is φ = 52087424.

The previous prime is 78131113. The next prime is 78131143. The reversal of 78131139 is 93113187.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 93113187 = 3 ⋅31037729.

It is a cyclic number.

It is not a de Polignac number, because 78131139 - 2⁵ = 78131107 is a prime.

It is a super-2 number, since 2×78131139² = 12208949762874642, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78131149) 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 in 3 ways as a sum of consecutive naturals, for example, 13021854 + ... + 13021859.

It is an arithmetic number, because the mean of its divisors is an integer number (26043714).

Almost surely, 2^78131139 is an apocalyptic number.

78131139 is a deficient number, since it is larger than the sum of its proper divisors (26043717).

78131139 is a wasteful number, since it uses less digits than its factorization.

78131139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26043716.

The product of its digits is 4536, while the sum is 33.

The square root of 78131139 is about 8839.1820322924. The cubic root of 78131139 is about 427.5051837544.

The spelling of 78131139 in words is "seventy-eight million, one hundred thirty-one thousand, one hundred thirty-nine".