78816831 has 4 divisors (see below), whose sum is σ = 105089112. Its totient is φ = 52544552.

The previous prime is 78816823. The next prime is 78816851. The reversal of 78816831 is 13861887.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 78816831 - 2³ = 78816823 is a prime.

It is a super-2 number, since 2×78816831² = 12424185697765122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78816851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13136136 + ... + 13136141.

It is an arithmetic number, because the mean of its divisors is an integer number (26272278).

Almost surely, 2^78816831 is an apocalyptic number.

78816831 is a deficient number, since it is larger than the sum of its proper divisors (26272281).

78816831 is a wasteful number, since it uses less digits than its factorization.

78816831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26272280.

The product of its digits is 64512, while the sum is 42.

The square root of 78816831 is about 8877.8843763590. The cubic root of 78816831 is about 428.7521620418.

The spelling of 78816831 in words is "seventy-eight million, eight hundred sixteen thousand, eight hundred thirty-one".