21434421 has 8 divisors (see below), whose sum is σ = 28600704. Its totient is φ = 14278880.

The previous prime is 21434417. The next prime is 21434429. The reversal of 21434421 is 12443412.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21434421 - 2² = 21434417 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 (21434429) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5860 + ... + 8786.

It is an arithmetic number, because the mean of its divisors is an integer number (3575088).

Almost surely, 2^21434421 is an apocalyptic number.

It is an amenable number.

21434421 is a deficient number, since it is larger than the sum of its proper divisors (7166283).

21434421 is a wasteful number, since it uses less digits than its factorization.

21434421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5371.

The product of its digits is 768, while the sum is 21.

The square root of 21434421 is about 4629.7322816768. The cubic root of 21434421 is about 277.7818838445.

Adding to 21434421 its reverse (12443412), we get a palindrome (33877833).

The spelling of 21434421 in words is "twenty-one million, four hundred thirty-four thousand, four hundred twenty-one".