21384845 has 16 divisors (see below), whose sum is σ = 26490240. Its totient is φ = 16564800.

The previous prime is 21384841. The next prime is 21384877. The reversal of 21384845 is 54848312.

It is not a de Polignac number, because 21384845 - 2² = 21384841 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21384841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 20435 + ... + 21455.

It is an arithmetic number, because the mean of its divisors is an integer number (1655640).

Almost surely, 2^21384845 is an apocalyptic number.

It is an amenable number.

21384845 is a deficient number, since it is larger than the sum of its proper divisors (5105395).

21384845 is a wasteful number, since it uses less digits than its factorization.

21384845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1156.

The product of its digits is 30720, while the sum is 35.

The square root of 21384845 is about 4624.3750929180. The cubic root of 21384845 is about 277.5675565306.

It can be divided in two parts, 213 and 84845, that added together give a palindrome (85058).

The spelling of 21384845 in words is "twenty-one million, three hundred eighty-four thousand, eight hundred forty-five".