81868647 has 8 divisors (see below), whose sum is σ = 124752256. Its totient is φ = 46782072.

The previous prime is 81868643. The next prime is 81868667. The reversal of 81868647 is 74686818.

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

It is not a de Polignac number, because 81868647 - 2² = 81868643 is a prime.

It is a super-2 number, since 2×81868647² = 13404950723221218, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81868596 and 81868605.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81868643) 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, 1949233 + ... + 1949274.

It is an arithmetic number, because the mean of its divisors is an integer number (15594032).

Almost surely, 2^81868647 is an apocalyptic number.

81868647 is a deficient number, since it is larger than the sum of its proper divisors (42883609).

81868647 is a wasteful number, since it uses less digits than its factorization.

81868647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3898517.

The product of its digits is 516096, while the sum is 48.

The square root of 81868647 is about 9048.1294752009. The cubic root of 81868647 is about 434.2160487170.

The spelling of 81868647 in words is "eighty-one million, eight hundred sixty-eight thousand, six hundred forty-seven".