21705848 has 16 divisors (see below), whose sum is σ = 40814880. Its totient is φ = 10821888.

The previous prime is 21705839. The next prime is 21705863. The reversal of 21705848 is 84850712.

It is a super-2 number, since 2×21705848² = 942287674798208, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 761 + ... + 6632.

It is an arithmetic number, because the mean of its divisors is an integer number (2550930).

Almost surely, 2^21705848 is an apocalyptic number.

It is an amenable number.

21705848 is a deficient number, since it is larger than the sum of its proper divisors (19109032).

21705848 is a wasteful number, since it uses less digits than its factorization.

21705848 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7766 (or 7762 counting only the distinct ones).

The product of its (nonzero) digits is 17920, while the sum is 35.

The square root of 21705848 is about 4658.9535305689. The cubic root of 21705848 is about 278.9494990450.

The spelling of 21705848 in words is "twenty-one million, seven hundred five thousand, eight hundred forty-eight".