81084931 has 2 divisors, whose sum is σ = 81084932. Its totient is φ = 81084930.

The previous prime is 81084929. The next prime is 81084937. The reversal of 81084931 is 13948018.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81084931 - 2¹ = 81084929 is a prime.

It is a super-2 number, since 2×81084931² = 13149532070549522, which contains 22 as substring.

Together with 81084929, it forms a pair of twin primes.

It is equal to p_4729165 and since 81084931 and 4729165 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (81084937) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40542465 + 40542466.

It is an arithmetic number, because the mean of its divisors is an integer number (40542466).

Almost surely, 2^81084931 is an apocalyptic number.

81084931 is a deficient number, since it is larger than the sum of its proper divisors (1).

81084931 is an equidigital number, since it uses as much as digits as its factorization.

81084931 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 34.

The square root of 81084931 is about 9004.7171526928. The cubic root of 81084931 is about 432.8260425874.

The spelling of 81084931 in words is "eighty-one million, eighty-four thousand, nine hundred thirty-one".