81384131 has 2 divisors, whose sum is σ = 81384132. Its totient is φ = 81384130.

The previous prime is 81384109. The next prime is 81384157. The reversal of 81384131 is 13148318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81384131 - 2²⁶ = 14275267 is a prime.

It is a super-2 number, since 2×81384131² = 13246753557250322, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 81384094 and 81384103.

It is not a weakly prime, because it can be changed into another prime (81384101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40692065 + 40692066.

It is an arithmetic number, because the mean of its divisors is an integer number (40692066).

Almost surely, 2^81384131 is an apocalyptic number.

81384131 is a deficient number, since it is larger than the sum of its proper divisors (1).

81384131 is an equidigital number, since it uses as much as digits as its factorization.

81384131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2304, while the sum is 29.

The square root of 81384131 is about 9021.3153697230. The cubic root of 81384131 is about 433.3577591097.

The spelling of 81384131 in words is "eighty-one million, three hundred eighty-four thousand, one hundred thirty-one".