81801869 has 8 divisors (see below), whose sum is σ = 86562432. Its totient is φ = 77141680.

The previous prime is 81801851. The next prime is 81801883. The reversal of 81801869 is 96810818.

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 81801869 - 2⁸ = 81801613 is a prime.

It is a super-2 number, since 2×81801869² = 13383091543786322, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81801809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23414 + ... + 26679.

It is an arithmetic number, because the mean of its divisors is an integer number (10820304).

Almost surely, 2^81801869 is an apocalyptic number.

It is an amenable number.

81801869 is a deficient number, since it is larger than the sum of its proper divisors (4760563).

81801869 is a wasteful number, since it uses less digits than its factorization.

81801869 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50187.

The product of its (nonzero) digits is 27648, while the sum is 41.

The square root of 81801869 is about 9044.4385674292. The cubic root of 81801869 is about 434.0979572468.

The spelling of 81801869 in words is "eighty-one million, eight hundred one thousand, eight hundred sixty-nine".