78158781 has 12 divisors (see below), whose sum is σ = 116538240. Its totient is φ = 50424840.

The previous prime is 78158779. The next prime is 78158813. The reversal of 78158781 is 18785187.

It is not a de Polignac number, because 78158781 - 2¹ = 78158779 is a prime.

It is a super-2 number, since 2×78158781² = 12217590094811922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78158081) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 139791 + ... + 140348.

It is an arithmetic number, because the mean of its divisors is an integer number (9711520).

Almost surely, 2^78158781 is an apocalyptic number.

It is an amenable number.

78158781 is a deficient number, since it is larger than the sum of its proper divisors (38379459).

78158781 is a wasteful number, since it uses less digits than its factorization.

78158781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 280176 (or 280173 counting only the distinct ones).

The product of its digits is 125440, while the sum is 45.

The square root of 78158781 is about 8840.7455002392. The cubic root of 78158781 is about 427.5555934678. Note that the first 4 decimals are identical.

The spelling of 78158781 in words is "seventy-eight million, one hundred fifty-eight thousand, seven hundred eighty-one".