18681818 has 8 divisors (see below), whose sum is σ = 28780212. Its totient is φ = 9088416.

The previous prime is 18681797. The next prime is 18681833. The reversal of 18681818 is 81818681.

It can be written as a sum of positive squares in 2 ways, for example, as 18037009 + 644809 = 4247^2 + 803^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 126155 + ... + 126302.

Almost surely, 2^18681818 is an apocalyptic number.

18681818 is a deficient number, since it is larger than the sum of its proper divisors (10098394).

18681818 is a wasteful number, since it uses less digits than its factorization.

18681818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 252496.

The product of its digits is 24576, while the sum is 41.

The square root of 18681818 is about 4322.2468693956. The cubic root of 18681818 is about 265.3422325716.

The spelling of 18681818 in words is "eighteen million, six hundred eighty-one thousand, eight hundred eighteen".