81810659 has 8 divisors (see below), whose sum is σ = 94094688. Its totient is φ = 69675840.

The previous prime is 81810649. The next prime is 81810661. The reversal of 81810659 is 95601818.

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

It is a cyclic number.

It is not a de Polignac number, because 81810659 - 2¹² = 81806563 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81810649) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36122 + ... + 38319.

It is an arithmetic number, because the mean of its divisors is an integer number (11761836).

Almost surely, 2^81810659 is an apocalyptic number.

81810659 is a deficient number, since it is larger than the sum of its proper divisors (12284029).

81810659 is a wasteful number, since it uses less digits than its factorization.

81810659 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 74605.

The product of its (nonzero) digits is 17280, while the sum is 38.

The square root of 81810659 is about 9044.9244883526. The cubic root of 81810659 is about 434.1135053202.

The spelling of 81810659 in words is "eighty-one million, eight hundred ten thousand, six hundred fifty-nine".