81858670 has 16 divisors (see below), whose sum is σ = 150773040. Its totient is φ = 31981824.

The previous prime is 81858661. The next prime is 81858671. The reversal of 81858670 is 7685818.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81858671) 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 7 ways as a sum of consecutive naturals, for example, 94755 + ... + 95614.

It is an arithmetic number, because the mean of its divisors is an integer number (9423315).

Almost surely, 2^81858670 is an apocalyptic number.

81858670 is a deficient number, since it is larger than the sum of its proper divisors (68914370).

81858670 is a wasteful number, since it uses less digits than its factorization.

81858670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 190419.

The product of its (nonzero) digits is 107520, while the sum is 43.

The square root of 81858670 is about 9047.5781289802. The cubic root of 81858670 is about 434.1984092841.

It can be divided in two parts, 81858 and 670, that added together give a palindrome (82528).

The spelling of 81858670 in words is "eighty-one million, eight hundred fifty-eight thousand, six hundred seventy".