21626838 has 20 divisors (see below), whose sum is σ = 48460500. Its totient is φ = 7208892.

The previous prime is 21626819. The next prime is 21626881. The reversal of 21626838 is 83862612.

21626838 is a `hidden beast` number, since 21 + 626 + 8 + 3 + 8 = 666.

It is a congruent number.

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 9 ways as a sum of consecutive naturals, for example, 66588 + ... + 66911.

It is an arithmetic number, because the mean of its divisors is an integer number (2423025).

Almost surely, 2^21626838 is an apocalyptic number.

21626838 is an abundant number, since it is smaller than the sum of its proper divisors (26833662).

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

21626838 is a wasteful number, since it uses less digits than its factorization.

21626838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133513 (or 133504 counting only the distinct ones).

The product of its digits is 27648, while the sum is 36.

The square root of 21626838 is about 4650.4664282199. The cubic root of 21626838 is about 278.6106257608.

The spelling of 21626838 in words is "twenty-one million, six hundred twenty-six thousand, eight hundred thirty-eight".