20581872 has 80 divisors (see below), whose sum is σ = 56329728. Its totient is φ = 6462720.

The previous prime is 20581871. The next prime is 20581901. The reversal of 20581872 is 27818502.

It is a super-2 number, since 2×20581872² = 847226910048768, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20581871) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 113622 + ... + 113802.

Almost surely, 2^20581872 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 20581872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28164864).

20581872 is an abundant number, since it is smaller than the sum of its proper divisors (35747856).

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

20581872 is a wasteful number, since it uses less digits than its factorization.

20581872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318 (or 312 counting only the distinct ones).

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

The square root of 20581872 is about 4536.7248098160. The cubic root of 20581872 is about 274.0490437367.

The spelling of 20581872 in words is "twenty million, five hundred eighty-one thousand, eight hundred seventy-two".