21775856 has 20 divisors (see below), whose sum is σ = 42439992. Its totient is φ = 10823616.

The previous prime is 21775837. The next prime is 21775877. The reversal of 21775856 is 65857712.

It is a hoax number, since the sum of its digits (41) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

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, 1166 + ... + 6701.

Almost surely, 2^21775856 is an apocalyptic number.

It is an amenable number.

21775856 is a deficient number, since it is larger than the sum of its proper divisors (20664136).

21775856 is a wasteful number, since it uses less digits than its factorization.

21775856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8048 (or 8042 counting only the distinct ones).

The product of its digits is 117600, while the sum is 41.

The square root of 21775856 is about 4666.4607573621. The cubic root of 21775856 is about 279.2490763560.

The spelling of 21775856 in words is "twenty-one million, seven hundred seventy-five thousand, eight hundred fifty-six".