81994601 has 8 divisors (see below), whose sum is σ = 89799360. Its totient is φ = 74403792.

The previous prime is 81994589. The next prime is 81994639. The reversal of 81994601 is 10649918.

It is a happy number.

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 81994601 - 2⁶ = 81994537 is a prime.

It is a super-2 number, since 2×81994601² = 13446229186298402, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81994681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52685 + ... + 54218.

It is an arithmetic number, because the mean of its divisors is an integer number (11224920).

Almost surely, 2^81994601 is an apocalyptic number.

It is an amenable number.

81994601 is a deficient number, since it is larger than the sum of its proper divisors (7804759).

81994601 is a wasteful number, since it uses less digits than its factorization.

81994601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106975.

The product of its (nonzero) digits is 15552, while the sum is 38.

The square root of 81994601 is about 9055.0870233256. The cubic root of 81994601 is about 434.4386134670.

The spelling of 81994601 in words is "eighty-one million, nine hundred ninety-four thousand, six hundred one".