21821434 has 8 divisors (see below), whose sum is σ = 34155360. Its totient is φ = 10436316.

The previous prime is 21821419. The next prime is 21821441. The reversal of 21821434 is 43412812.

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

It is a junction number, because it is equal to n+sod(n) for n = 21821399 and 21821408.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 237144 + ... + 237235.

It is an arithmetic number, because the mean of its divisors is an integer number (4269420).

Almost surely, 2^21821434 is an apocalyptic number.

21821434 is a deficient number, since it is larger than the sum of its proper divisors (12333926).

21821434 is a wasteful number, since it uses less digits than its factorization.

21821434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 474404.

The product of its digits is 1536, while the sum is 25.

The square root of 21821434 is about 4671.3417772627. The cubic root of 21821434 is about 279.4437682028.

The spelling of 21821434 in words is "twenty-one million, eight hundred twenty-one thousand, four hundred thirty-four".