81818619 has 16 divisors (see below), whose sum is σ = 110950272. Its totient is φ = 53621568.

The previous prime is 81818609. The next prime is 81818621. The reversal of 81818619 is 91681818.

It is not a de Polignac number, because 81818619 - 2¹¹ = 81816571 is a prime.

It is a super-2 number, since 2×81818619² = 13388572830134322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81818609) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 119452 + ... + 120134.

It is an arithmetic number, because the mean of its divisors is an integer number (6934392).

Almost surely, 2^81818619 is an apocalyptic number.

81818619 is a deficient number, since it is larger than the sum of its proper divisors (29131653).

81818619 is a wasteful number, since it uses less digits than its factorization.

81818619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306.

The product of its digits is 27648, while the sum is 42.

The square root of 81818619 is about 9045.3645034349. The cubic root of 81818619 is about 434.1275842983.

The spelling of 81818619 in words is "eighty-one million, eight hundred eighteen thousand, six hundred nineteen".