21171722 has 16 divisors (see below), whose sum is σ = 37310112. Its totient is φ = 8883120.

The previous prime is 21171713. The next prime is 21171727. The reversal of 21171722 is 22717112.

It is not an unprimeable number, because it can be changed into a prime (21171727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36728 + ... + 37299.

It is an arithmetic number, because the mean of its divisors is an integer number (2331882).

Almost surely, 2^21171722 is an apocalyptic number.

21171722 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21171722 is a deficient number, since it is larger than the sum of its proper divisors (16138390).

21171722 is a wasteful number, since it uses less digits than its factorization.

21171722 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74053.

The product of its digits is 392, while the sum is 23.

The square root of 21171722 is about 4601.2739540262. The cubic root of 21171722 is about 276.6423897667.

Adding to 21171722 its reverse (22717112), we get a palindrome (43888834).

The spelling of 21171722 in words is "twenty-one million, one hundred seventy-one thousand, seven hundred twenty-two".