20811536 has 40 divisors (see below), whose sum is σ = 44952480. Its totient is φ = 9275904.

The previous prime is 20811521. The next prime is 20811541. The reversal of 20811536 is 63511802.

It is a zygodrome in base 3.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3155 + ... + 7181.

It is an arithmetic number, because the mean of its divisors is an integer number (1123812).

Almost surely, 2^20811536 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 20811536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22476240).

20811536 is an abundant number, since it is smaller than the sum of its proper divisors (24140944).

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

20811536 is a wasteful number, since it uses less digits than its factorization.

20811536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4071 (or 4065 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 20811536 is about 4561.9662427510. The cubic root of 20811536 is about 275.0646063083.

The spelling of 20811536 in words is "twenty million, eight hundred eleven thousand, five hundred thirty-six".