20811264 has 80 divisors (see below), whose sum is σ = 58777488. Its totient is φ = 6520832.

The previous prime is 20811257. The next prime is 20811283. The reversal of 20811264 is 46211802.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a congruent number.

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, 25714 + ... + 26510.

Almost surely, 2^20811264 is an apocalyptic number.

20811264 is a gapful number since it is divisible by the number (24) 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 20811264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29388744).

20811264 is an abundant number, since it is smaller than the sum of its proper divisors (37966224).

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

20811264 is an equidigital number, since it uses as much as digits as its factorization.

20811264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 835 (or 819 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 20811264 is about 4561.9364309468. The cubic root of 20811264 is about 275.0634079682.

The spelling of 20811264 in words is "twenty million, eight hundred eleven thousand, two hundred sixty-four".