16221816 has 128 divisors (see below), whose sum is σ = 49896000. Its totient is φ = 4852224.

The previous prime is 16221761. The next prime is 16221823. The reversal of 16221816 is 61812261.

It is a hoax number, since the sum of its digits (27) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 16221816.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 148770 + ... + 148878.

Almost surely, 2^16221816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16221816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24948000).

16221816 is an abundant number, since it is smaller than the sum of its proper divisors (33674184).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

16221816 is a wasteful number, since it uses less digits than its factorization.

16221816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190 (or 180 counting only the distinct ones).

The product of its digits is 1152, while the sum is 27.

The square root of 16221816 is about 4027.6315620970. The cubic root of 16221816 is about 253.1433309084.

The spelling of 16221816 in words is "sixteen million, two hundred twenty-one thousand, eight hundred sixteen".