81493646 has 16 divisors (see below), whose sum is σ = 137368224. Its totient is φ = 35976864.

The previous prime is 81493639. The next prime is 81493667. The reversal of 81493646 is 64639418.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67541 + ... + 68736.

It is an arithmetic number, because the mean of its divisors is an integer number (8585514).

Almost surely, 2^81493646 is an apocalyptic number.

81493646 is a deficient number, since it is larger than the sum of its proper divisors (55874578).

81493646 is a wasteful number, since it uses less digits than its factorization.

81493646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136315.

The product of its digits is 124416, while the sum is 41.

The square root of 81493646 is about 9027.3831202625. The cubic root of 81493646 is about 433.5520553949.

The spelling of 81493646 in words is "eighty-one million, four hundred ninety-three thousand, six hundred forty-six".