81819801 has 48 divisors (see below), whose sum is σ = 141732864. Its totient is φ = 46201104.

The previous prime is 81819799. The next prime is 81819889. The reversal of 81819801 is 10891818.

It is not a de Polignac number, because 81819801 - 2¹ = 81819799 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81819601) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 174970 + ... + 175436.

It is an arithmetic number, because the mean of its divisors is an integer number (2952768).

Almost surely, 2^81819801 is an apocalyptic number.

81819801 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

81819801 is a deficient number, since it is larger than the sum of its proper divisors (59913063).

81819801 is a wasteful number, since it uses less digits than its factorization.

81819801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592 (or 580 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 36.

The square root of 81819801 is about 9045.4298405327. The cubic root of 81819801 is about 434.1296748426.

The spelling of 81819801 in words is "eighty-one million, eight hundred nineteen thousand, eight hundred one".