20018656 has 72 divisors (see below), whose sum is σ = 48607776. Its totient is φ = 8064000.

The previous prime is 20018651. The next prime is 20018659. The reversal of 20018656 is 65681002.

It is a super-3 number, since 3×20018656³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (28).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20018651) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 26281 + ... + 27031.

It is an arithmetic number, because the mean of its divisors is an integer number (675108).

Almost surely, 2^20018656 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20018656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24303888).

20018656 is an abundant number, since it is smaller than the sum of its proper divisors (28589120).

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

20018656 is a wasteful number, since it uses less digits than its factorization.

20018656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 792 (or 777 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 20018656 is about 4474.2212730262. The cubic root of 20018656 is about 271.5261357220.

Subtracting from 20018656 its sum of digits (28), we obtain a triangular number (20018628 = T₆₃₂₇).

Adding to 20018656 its reverse (65681002), we get a palindrome (85699658).

The spelling of 20018656 in words is "twenty million, eighteen thousand, six hundred fifty-six".