81819445 has 8 divisors (see below), whose sum is σ = 98233344. Its totient is φ = 65422224.

The previous prime is 81819443. The next prime is 81819449. The reversal of 81819445 is 54491818.

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 81819445 - 2¹ = 81819443 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81819398 and 81819407.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81819443) 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, 13252 + ... + 18418.

It is an arithmetic number, because the mean of its divisors is an integer number (12279168).

Almost surely, 2^81819445 is an apocalyptic number.

It is an amenable number.

81819445 is a deficient number, since it is larger than the sum of its proper divisors (16413899).

81819445 is a wasteful number, since it uses less digits than its factorization.

81819445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8339.

The product of its digits is 46080, while the sum is 40.

The square root of 81819445 is about 9045.4101620656. The cubic root of 81819445 is about 434.1290452053.

The spelling of 81819445 in words is "eighty-one million, eight hundred nineteen thousand, four hundred forty-five".