81858135 has 32 divisors (see below), whose sum is σ = 135843840. Its totient is φ = 42048000.

The previous prime is 81858131. The next prime is 81858149. The reversal of 81858135 is 53185818.

It is not a de Polignac number, because 81858135 - 2² = 81858131 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81858093 and 81858102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81858131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 186246 + ... + 186684.

It is an arithmetic number, because the mean of its divisors is an integer number (4245120).

Almost surely, 2^81858135 is an apocalyptic number.

81858135 is a deficient number, since it is larger than the sum of its proper divisors (53985705).

81858135 is a wasteful number, since it uses less digits than its factorization.

81858135 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 879.

The product of its digits is 38400, while the sum is 39.

The square root of 81858135 is about 9047.5485630087. The cubic root of 81858135 is about 434.1974633584.

It can be divided in two parts, 8185813 and 5, that added together give a palindrome (8185818).

The spelling of 81858135 in words is "eighty-one million, eight hundred fifty-eight thousand, one hundred thirty-five".