21934638 has 72 divisors (see below), whose sum is σ = 54318264. Its totient is φ = 6629040.

The previous prime is 21934613. The next prime is 21934667. The reversal of 21934638 is 83643912.

21934638 is a `hidden beast` number, since 2 + 19 + 3 + 4 + 638 = 666.

It is a super-2 number, since 2×21934638² = 962256688382088, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 58620 + ... + 58992.

Almost surely, 2^21934638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21934638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27159132).

21934638 is an abundant number, since it is smaller than the sum of its proper divisors (32383626).

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

21934638 is a wasteful number, since it uses less digits than its factorization.

21934638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412 (or 389 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 21934638 is about 4683.4429643159. The cubic root of 21934638 is about 279.9261625032.

The spelling of 21934638 in words is "twenty-one million, nine hundred thirty-four thousand, six hundred thirty-eight".