20728518 has 8 divisors (see below), whose sum is σ = 41457048. Its totient is φ = 6909504.

The previous prime is 20728517. The next prime is 20728531. The reversal of 20728518 is 81582702.

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

20728518 is an admirable number.

It is a super-3 number, since 3×20728518³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20728517) 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, 1727371 + ... + 1727382.

It is an arithmetic number, because the mean of its divisors is an integer number (5182131).

Almost surely, 2^20728518 is an apocalyptic number.

20728518 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20728518 is a wasteful number, since it uses less digits than its factorization.

20728518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3454758.

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 20728518 is about 4552.8582231385. The cubic root of 20728518 is about 274.6983712132.

The spelling of 20728518 in words is "twenty million, seven hundred twenty-eight thousand, five hundred eighteen".