20671728 has 240 divisors, whose sum is σ = 73281024. Its totient is φ = 4945920.

The previous prime is 20671723. The next prime is 20671757. The reversal of 20671728 is 82717602.

It is a hoax number, since the sum of its digits (33) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20671723) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 439801 + ... + 439847.

Almost surely, 2^20671728 is an apocalyptic number.

20671728 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20671728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36640512).

20671728 is an abundant number, since it is smaller than the sum of its proper divisors (52609296).

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

20671728 is a wasteful number, since it uses less digits than its factorization.

20671728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100 (or 87 counting only the distinct ones).

The product of its (nonzero) digits is 9408, while the sum is 33.

The square root of 20671728 is about 4546.6172040320. The cubic root of 20671728 is about 274.4472777069.

The spelling of 20671728 in words is "twenty million, six hundred seventy-one thousand, seven hundred twenty-eight".