21172010 has 16 divisors (see below), whose sum is σ = 38212776. Its totient is φ = 8445888.

The previous prime is 21172009. The next prime is 21172037. The reversal of 21172010 is 1027112.

It can be written as a sum of positive squares in 4 ways, for example, as 21169201 + 2809 = 4601^2 + 53^2 .

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 7 ways as a sum of consecutive naturals, for example, 1304 + ... + 6636.

Almost surely, 2^21172010 is an apocalyptic number.

21172010 is a deficient number, since it is larger than the sum of its proper divisors (17040766).

21172010 is a wasteful number, since it uses less digits than its factorization.

21172010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5737.

The product of its (nonzero) digits is 28, while the sum is 14.

The square root of 21172010 is about 4601.3052496004. The cubic root of 21172010 is about 276.6436441545.

Adding to 21172010 its reverse (1027112), we get a palindrome (22199122).

The spelling of 21172010 in words is "twenty-one million, one hundred seventy-two thousand, ten".