21748388 has 12 divisors (see below), whose sum is σ = 40062960. Its totient is φ = 10301832.

The previous prime is 21748367. The next prime is 21748399. The reversal of 21748388 is 88384712.

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 3 ways as a sum of consecutive naturals, for example, 143006 + ... + 143157.

It is an arithmetic number, because the mean of its divisors is an integer number (3338580).

Almost surely, 2^21748388 is an apocalyptic number.

It is an amenable number.

21748388 is a deficient number, since it is larger than the sum of its proper divisors (18314572).

21748388 is a wasteful number, since it uses less digits than its factorization.

21748388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286186 (or 286184 counting only the distinct ones).

The product of its digits is 86016, while the sum is 41.

The square root of 21748388 is about 4663.5166988015. The cubic root of 21748388 is about 279.1316123010.

The spelling of 21748388 in words is "twenty-one million, seven hundred forty-eight thousand, three hundred eighty-eight".