81811401 has 8 divisors (see below), whose sum is σ = 124665024. Its totient is φ = 46749360.

The previous prime is 81811399. The next prime is 81811409. The reversal of 81811401 is 10411818.

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

It is not a de Polignac number, because 81811401 - 2¹ = 81811399 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81811409) 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, 1947870 + ... + 1947911.

It is an arithmetic number, because the mean of its divisors is an integer number (15583128).

Almost surely, 2^81811401 is an apocalyptic number.

It is an amenable number.

81811401 is a deficient number, since it is larger than the sum of its proper divisors (42853623).

81811401 is a wasteful number, since it uses less digits than its factorization.

81811401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3895791.

The product of its (nonzero) digits is 256, while the sum is 24.

The square root of 81811401 is about 9044.9655057385. The cubic root of 81811401 is about 434.1148177460.

The spelling of 81811401 in words is "eighty-one million, eight hundred eleven thousand, four hundred one".