21509848 has 8 divisors (see below), whose sum is σ = 40330980. Its totient is φ = 10754920.

The previous prime is 21509837. The next prime is 21509849. The reversal of 21509848 is 84890512.

It is a tau number, because it is divible by the number of its divisors (8).

It is a hoax number, since the sum of its digits (37) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21509849) 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 as a sum of consecutive naturals, namely, 1344358 + ... + 1344373.

Almost surely, 2^21509848 is an apocalyptic number.

It is an amenable number.

21509848 is a deficient number, since it is larger than the sum of its proper divisors (18821132).

21509848 is a wasteful number, since it uses less digits than its factorization.

21509848 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2688737 (or 2688733 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 37.

The square root of 21509848 is about 4637.8710633220. The cubic root of 21509848 is about 278.1073373962.

The spelling of 21509848 in words is "twenty-one million, five hundred nine thousand, eight hundred forty-eight".