81469139 has 2 divisors, whose sum is σ = 81469140. Its totient is φ = 81469138.

The previous prime is 81469127. The next prime is 81469187. The reversal of 81469139 is 93196418.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81469139 - 2⁸ = 81468883 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81469096 and 81469105.

It is not a weakly prime, because it can be changed into another prime (81469939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40734569 + 40734570.

It is an arithmetic number, because the mean of its divisors is an integer number (40734570).

Almost surely, 2^81469139 is an apocalyptic number.

81469139 is a deficient number, since it is larger than the sum of its proper divisors (1).

81469139 is an equidigital number, since it uses as much as digits as its factorization.

81469139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 46656, while the sum is 41.

The square root of 81469139 is about 9026.0256480912. The cubic root of 81469139 is about 433.5085913705.

The spelling of 81469139 in words is "eighty-one million, four hundred sixty-nine thousand, one hundred thirty-nine".