21149816 has 16 divisors (see below), whose sum is σ = 41023800. Its totient is φ = 10210144.

The previous prime is 21149813. The next prime is 21149833. The reversal of 21149816 is 61894112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21149813) 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 3 ways as a sum of consecutive naturals, for example, 45350 + ... + 45813.

Almost surely, 2^21149816 is an apocalyptic number.

It is an amenable number.

21149816 is a deficient number, since it is larger than the sum of its proper divisors (19873984).

21149816 is a wasteful number, since it uses less digits than its factorization.

21149816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 91198 (or 91194 counting only the distinct ones).

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

The square root of 21149816 is about 4598.8929102557. The cubic root of 21149816 is about 276.5469445388.

The spelling of 21149816 in words is "twenty-one million, one hundred forty-nine thousand, eight hundred sixteen".