20815018 has 8 divisors (see below), whose sum is σ = 35682912. Its totient is φ = 8920716.

The previous prime is 20815007. The next prime is 20815019. The reversal of 20815018 is 81051802.

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

It is a junction number, because it is equal to n+sod(n) for n = 20814983 and 20815001.

It is not an unprimeable number, because it can be changed into a prime (20815019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 743380 + ... + 743407.

It is an arithmetic number, because the mean of its divisors is an integer number (4460364).

Almost surely, 2^20815018 is an apocalyptic number.

20815018 is a deficient number, since it is larger than the sum of its proper divisors (14867894).

20815018 is a wasteful number, since it uses less digits than its factorization.

20815018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1486796.

The product of its (nonzero) digits is 640, while the sum is 25.

The square root of 20815018 is about 4562.3478604771. The cubic root of 20815018 is about 275.0799459025.

The spelling of 20815018 in words is "twenty million, eight hundred fifteen thousand, eighteen".