78131811 has 16 divisors (see below), whose sum is σ = 108039168. Its totient is φ = 50172000.

The previous prime is 78131791. The next prime is 78131821. The reversal of 78131811 is 11813187.

It is a happy number.

It is not a de Polignac number, because 78131811 - 2⁶ = 78131747 is a prime.

It is a super-2 number, since 2×78131811² = 12209159780279442, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78131821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19261 + ... + 22961.

It is an arithmetic number, because the mean of its divisors is an integer number (6752448).

Almost surely, 2^78131811 is an apocalyptic number.

78131811 is a deficient number, since it is larger than the sum of its proper divisors (29907357).

78131811 is a wasteful number, since it uses less digits than its factorization.

78131811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3962.

The product of its digits is 1344, while the sum is 30.

The square root of 78131811 is about 8839.2200447777. The cubic root of 78131811 is about 427.5064093974.

Adding to 78131811 its reverse (11813187), we get a palindrome (89944998).

The spelling of 78131811 in words is "seventy-eight million, one hundred thirty-one thousand, eight hundred eleven".