81349618 has 16 divisors (see below), whose sum is σ = 141223680. Its totient is φ = 34422336.

The previous prime is 81349603. The next prime is 81349633. The reversal of 81349618 is 81694318.

It is an interprime number because it is at equal distance from previous prime (81349603) and next prime (81349633).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35671 + ... + 37882.

It is an arithmetic number, because the mean of its divisors is an integer number (8826480).

Almost surely, 2^81349618 is an apocalyptic number.

81349618 is a deficient number, since it is larger than the sum of its proper divisors (59874062).

81349618 is a wasteful number, since it uses less digits than its factorization.

81349618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73641.

The product of its digits is 41472, while the sum is 40.

The square root of 81349618 is about 9019.4023083572. The cubic root of 81349618 is about 433.2964916739.

The spelling of 81349618 in words is "eighty-one million, three hundred forty-nine thousand, six hundred eighteen".