20806408 has 32 divisors (see below), whose sum is σ = 45221760. Its totient is φ = 8789760.

The previous prime is 20806397. The next prime is 20806417. The reversal of 20806408 is 80460802.

It is a super-2 number, since 2×20806408² = 865813227724928, which contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1360 + ... + 6592.

It is an arithmetic number, because the mean of its divisors is an integer number (1413180).

Almost surely, 2^20806408 is an apocalyptic number.

20806408 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 20806408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22610880).

20806408 is an abundant number, since it is smaller than the sum of its proper divisors (24415352).

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

20806408 is a wasteful number, since it uses less digits than its factorization.

20806408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5317 (or 5313 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 28.

The square root of 20806408 is about 4561.4041697705. The cubic root of 20806408 is about 275.0420123141.

It can be divided in two parts, 20806 and 408, that multiplied together give a palindrome (8488848).

The spelling of 20806408 in words is "twenty million, eight hundred six thousand, four hundred eight".