21213834 has 8 divisors (see below), whose sum is σ = 42427680. Its totient is φ = 7071276.

The previous prime is 21213811. The next prime is 21213847. The reversal of 21213834 is 43831212.

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

21213834 is an admirable 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 3 ways as a sum of consecutive naturals, for example, 1767814 + ... + 1767825.

It is an arithmetic number, because the mean of its divisors is an integer number (5303460).

Almost surely, 2^21213834 is an apocalyptic number.

21213834 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21213834 is a wasteful number, since it uses less digits than its factorization.

21213834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3535644.

The product of its digits is 1152, while the sum is 24.

The square root of 21213834 is about 4605.8478046935. The cubic root of 21213834 is about 276.8256884871.

The spelling of 21213834 in words is "twenty-one million, two hundred thirteen thousand, eight hundred thirty-four".