21383845 has 12 divisors (see below), whose sum is σ = 29850444. Its totient is φ = 14663040.

The previous prime is 21383839. The next prime is 21383863. The reversal of 21383845 is 54838312.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 16144324 + 5239521 = 4018^2 + 2289^2 .

It is not a de Polignac number, because 21383845 - 2¹⁹ = 20859557 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21383845.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 43396 + ... + 43885.

It is an arithmetic number, because the mean of its divisors is an integer number (2487537).

Almost surely, 2^21383845 is an apocalyptic number.

It is an amenable number.

21383845 is a deficient number, since it is larger than the sum of its proper divisors (8466599).

21383845 is an equidigital number, since it uses as much as digits as its factorization.

21383845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87300 (or 87293 counting only the distinct ones).

The product of its digits is 23040, while the sum is 34.

The square root of 21383845 is about 4624.2669689368. The cubic root of 21383845 is about 277.5632299170.

The spelling of 21383845 in words is "twenty-one million, three hundred eighty-three thousand, eight hundred forty-five".