81658369 has 8 divisors (see below), whose sum is σ = 88502120. Its totient is φ = 74894976.

The previous prime is 81658351. The next prime is 81658387. The reversal of 81658369 is 96385618.

It is an interprime number because it is at equal distance from previous prime (81658351) and next prime (81658387).

It can be written as a sum of positive squares in 4 ways, for example, as 16646400 + 65011969 = 4080^2 + 8063^2 .

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

It is not a de Polignac number, because 81658369 - 2¹⁵ = 81625601 is a prime.

It is a super-2 number, since 2×81658369² = 13336178455480322, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81658069) 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, 17964 + ... + 22045.

It is an arithmetic number, because the mean of its divisors is an integer number (11062765).

Almost surely, 2^81658369 is an apocalyptic number.

It is an amenable number.

81658369 is a deficient number, since it is larger than the sum of its proper divisors (6843751).

81658369 is a wasteful number, since it uses less digits than its factorization.

81658369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40179.

The product of its digits is 311040, while the sum is 46.

The square root of 81658369 is about 9036.5020334198. The cubic root of 81658369 is about 433.8439715340.

The spelling of 81658369 in words is "eighty-one million, six hundred fifty-eight thousand, three hundred sixty-nine".