81442615 has 8 divisors (see below), whose sum is σ = 98680608. Its totient is φ = 64521120.

The previous prime is 81442583. The next prime is 81442619. The reversal of 81442615 is 51624418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 81442615 - 2⁵ = 81442583 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81442619) by changing a digit.

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, 78556 + ... + 79585.

It is an arithmetic number, because the mean of its divisors is an integer number (12335076).

Almost surely, 2^81442615 is an apocalyptic number.

81442615 is a deficient number, since it is larger than the sum of its proper divisors (17237993).

81442615 is a wasteful number, since it uses less digits than its factorization.

81442615 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158249.

The product of its digits is 7680, while the sum is 31.

The square root of 81442615 is about 9024.5562217762. The cubic root of 81442615 is about 433.4615403027.

The spelling of 81442615 in words is "eighty-one million, four hundred forty-two thousand, six hundred fifteen".