21019838 has 32 divisors (see below), whose sum is σ = 38914560. Its totient is φ = 8316000.

The previous prime is 21019799. The next prime is 21019841. The reversal of 21019838 is 83891012.

It is a Curzon number.

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 15 ways as a sum of consecutive naturals, for example, 8213 + ... + 10463.

It is an arithmetic number, because the mean of its divisors is an integer number (1216080).

Almost surely, 2^21019838 is an apocalyptic number.

21019838 is a deficient number, since it is larger than the sum of its proper divisors (17894722).

21019838 is a wasteful number, since it uses less digits than its factorization.

21019838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2312.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 21019838 is about 4584.7396872669. The cubic root of 21019838 is about 275.9792657532.

The spelling of 21019838 in words is "twenty-one million, nineteen thousand, eight hundred thirty-eight".