21149838 has 24 divisors (see below), whose sum is σ = 45913608. Its totient is φ = 7036272.

The previous prime is 21149837. The next prime is 21149839. The reversal of 21149838 is 83894112.

It is an interprime number because it is at equal distance from previous prime (21149837) and next prime (21149839).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21149833) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 13420 + ... + 14912.

It is an arithmetic number, because the mean of its divisors is an integer number (1913067).

Almost surely, 2^21149838 is an apocalyptic number.

21149838 is an abundant number, since it is smaller than the sum of its proper divisors (24763770).

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

21149838 is a wasteful number, since it uses less digits than its factorization.

21149838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2288 (or 2285 counting only the distinct ones).

The product of its digits is 13824, while the sum is 36.

The square root of 21149838 is about 4598.8953021351. The cubic root of 21149838 is about 276.5470404267.

The spelling of 21149838 in words is "twenty-one million, one hundred forty-nine thousand, eight hundred thirty-eight".