21772005 has 32 divisors (see below), whose sum is σ = 37171200. Its totient is φ = 10850112.

The previous prime is 21772001. The next prime is 21772033. The reversal of 21772005 is 50027712.

It is not a de Polignac number, because 21772005 - 2² = 21772001 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21772001) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 22032 + ... + 22998.

It is an arithmetic number, because the mean of its divisors is an integer number (1161600).

Almost surely, 2^21772005 is an apocalyptic number.

It is an amenable number.

21772005 is a deficient number, since it is larger than the sum of its proper divisors (15399195).

21772005 is a wasteful number, since it uses less digits than its factorization.

21772005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073.

The product of its (nonzero) digits is 980, while the sum is 24.

The square root of 21772005 is about 4666.0481137682. The cubic root of 21772005 is about 279.2326139095.

Adding to 21772005 its reverse (50027712), we get a palindrome (71799717).

The spelling of 21772005 in words is "twenty-one million, seven hundred seventy-two thousand, five".