21016172 has 12 divisors (see below), whose sum is σ = 36810816. Its totient is φ = 10498800.

The previous prime is 21016159. The next prime is 21016187. The reversal of 21016172 is 27161012.

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, 6458 + ... + 9150.

It is an arithmetic number, because the mean of its divisors is an integer number (3067568).

Almost surely, 2^21016172 is an apocalyptic number.

It is an amenable number.

21016172 is a deficient number, since it is larger than the sum of its proper divisors (15794644).

21016172 is a wasteful number, since it uses less digits than its factorization.

21016172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4648 (or 4646 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 20.

The square root of 21016172 is about 4584.3398652369. The cubic root of 21016172 is about 275.9632206119.

Adding to 21016172 its reverse (27161012), we get a palindrome (48177184).

The spelling of 21016172 in words is "twenty-one million, sixteen thousand, one hundred seventy-two".