20891304 has 128 divisors (see below), whose sum is σ = 68140800. Its totient is φ = 5806080.

The previous prime is 20891293. The next prime is 20891333. The reversal of 20891304 is 40319802.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 61824 + ... + 62160.

It is an arithmetic number, because the mean of its divisors is an integer number (532350).

Almost surely, 2^20891304 is an apocalyptic number.

20891304 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 20891304, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34070400).

20891304 is an abundant number, since it is smaller than the sum of its proper divisors (47249496).

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

20891304 is a wasteful number, since it uses less digits than its factorization.

20891304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 400 (or 390 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 20891304 is about 4570.7006027523. The cubic root of 20891304 is about 275.4155876141.

The spelling of 20891304 in words is "twenty million, eight hundred ninety-one thousand, three hundred four".