21746320 has 20 divisors (see below), whose sum is σ = 50560380. Its totient is φ = 8698496.

The previous prime is 21746311. The next prime is 21746323. The reversal of 21746320 is 2364712.

It can be written as a sum of positive squares in 2 ways, for example, as 4804864 + 16941456 = 2192^2 + 4116^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21746323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 135835 + ... + 135994.

It is an arithmetic number, because the mean of its divisors is an integer number (2528019).

Almost surely, 2^21746320 is an apocalyptic number.

21746320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21746320 is an abundant number, since it is smaller than the sum of its proper divisors (28814060).

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

21746320 is a wasteful number, since it uses less digits than its factorization.

21746320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 271842 (or 271836 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 25.

The square root of 21746320 is about 4663.2949724417. The cubic root of 21746320 is about 279.1227647109.

The spelling of 21746320 in words is "twenty-one million, seven hundred forty-six thousand, three hundred twenty".