21004814 has 4 divisors (see below), whose sum is σ = 31507224. Its totient is φ = 10502406.

The previous prime is 21004813. The next prime is 21004829. The reversal of 21004814 is 41840012.

It is a semiprime because it is the product of two primes.

It is a super-3 number, since 3×21004814³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5251202 + ... + 5251205.

It is an arithmetic number, because the mean of its divisors is an integer number (7876806).

Almost surely, 2^21004814 is an apocalyptic number.

21004814 is a deficient number, since it is larger than the sum of its proper divisors (10502410).

21004814 is a wasteful number, since it uses less digits than its factorization.

21004814 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10502409.

The product of its (nonzero) digits is 256, while the sum is 20.

The square root of 21004814 is about 4583.1009153192. The cubic root of 21004814 is about 275.9134977115.

Adding to 21004814 its reverse (41840012), we get a palindrome (62844826).

The spelling of 21004814 in words is "twenty-one million, four thousand, eight hundred fourteen".