20681018 has 8 divisors (see below), whose sum is σ = 31041012. Its totient is φ = 10334016.

The previous prime is 20681009. The next prime is 20681021. The reversal of 20681018 is 81018602.

It can be written as a sum of positive squares in 2 ways, for example, as 20403289 + 277729 = 4517^2 + 527^2 .

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3746 + ... + 7442.

Almost surely, 2^20681018 is an apocalyptic number.

20681018 is a deficient number, since it is larger than the sum of its proper divisors (10359994).

20681018 is a wasteful number, since it uses less digits than its factorization.

20681018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6496.

The product of its (nonzero) digits is 768, while the sum is 26.

The square root of 20681018 is about 4547.6387279554. The cubic root of 20681018 is about 274.4883843070.

The spelling of 20681018 in words is "twenty million, six hundred eighty-one thousand, eighteen".