20643018 has 16 divisors (see below), whose sum is σ = 45039456. Its totient is φ = 6255440.

The previous prime is 20642971. The next prime is 20643043. The reversal of 20643018 is 81034602.

It is a happy number.

It is a super-2 number, since 2×20643018² = 852268384296648, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 156321 + ... + 156452.

It is an arithmetic number, because the mean of its divisors is an integer number (2814966).

Almost surely, 2^20643018 is an apocalyptic number.

20643018 is an abundant number, since it is smaller than the sum of its proper divisors (24396438).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20643018 is a wasteful number, since it uses less digits than its factorization.

20643018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312789.

The product of its (nonzero) digits is 1152, while the sum is 24.

The square root of 20643018 is about 4543.4588146037. The cubic root of 20643018 is about 274.3201631614.

The spelling of 20643018 in words is "twenty million, six hundred forty-three thousand, eighteen".