21775882 has 4 divisors (see below), whose sum is σ = 32663826. Its totient is φ = 10887940.

The previous prime is 21775877. The next prime is 21775889. The reversal of 21775882 is 28857712.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20985561 + 790321 = 4581^2 + 889^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (21775889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5443969 + ... + 5443972.

Almost surely, 2^21775882 is an apocalyptic number.

21775882 is a deficient number, since it is larger than the sum of its proper divisors (10887944).

21775882 is a wasteful number, since it uses less digits than its factorization.

21775882 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10887943.

The product of its digits is 62720, while the sum is 40.

The square root of 21775882 is about 4666.4635431984. The cubic root of 21775882 is about 279.2491874955.

The spelling of 21775882 in words is "twenty-one million, seven hundred seventy-five thousand, eight hundred eighty-two".