20801872 has 90 divisors (see below), whose sum is σ = 51091038. Its totient is φ = 8176896.

The previous prime is 20801849. The next prime is 20801873. The reversal of 20801872 is 27810802.

It can be written as a sum of positive squares in 3 ways, for example, as 226576 + 20575296 = 476^2 + 4536^2 .

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

20801872 is a modest number, since divided by 1872 gives 208 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 20801872.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20801873) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 132418 + ... + 132574.

Almost surely, 2^20801872 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 20801872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25545519).

20801872 is an abundant number, since it is smaller than the sum of its proper divisors (30289166).

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

20801872 is a wasteful number, since it uses less digits than its factorization.

20801872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205 (or 179 counting only the distinct ones).

The product of its (nonzero) digits is 1792, while the sum is 28.

The square root of 20801872 is about 4560.9069273556. The cubic root of 20801872 is about 275.0220235805.

The spelling of 20801872 in words is "twenty million, eight hundred one thousand, eight hundred seventy-two".