16821172 has 12 divisors (see below), whose sum is σ = 29524320. Its totient is φ = 8385656.

The previous prime is 16821139. The next prime is 16821173. The reversal of 16821172 is 27112861.

It is a self number, because there is not a number n which added to its sum of digits gives 16821172.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16821173) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4672 + ... + 7447.

It is an arithmetic number, because the mean of its divisors is an integer number (2460360).

Almost surely, 2^16821172 is an apocalyptic number.

It is an amenable number.

16821172 is a deficient number, since it is larger than the sum of its proper divisors (12703148).

16821172 is a wasteful number, since it uses less digits than its factorization.

16821172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12470 (or 12468 counting only the distinct ones).

The product of its digits is 1344, while the sum is 28.

The square root of 16821172 is about 4101.3622127288. The cubic root of 16821172 is about 256.2233768097.

The spelling of 16821172 in words is "sixteen million, eight hundred twenty-one thousand, one hundred seventy-two".