16403220 has 36 divisors (see below), whose sum is σ = 49756980. Its totient is φ = 4374144.

The previous prime is 16403197. The next prime is 16403227. The reversal of 16403220 is 2230461.

It is a happy number.

16403220 is a `hidden beast` number, since 1 + 640 + 3 + 2 + 20 = 666.

16403220 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 6780816 + 9622404 = 2604^2 + 3102^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 16403193 and 16403202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16403227) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 45385 + ... + 45744.

Almost surely, 2^16403220 is an apocalyptic number.

16403220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16403220 is an abundant number, since it is smaller than the sum of its proper divisors (33353760).

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

16403220 is a wasteful number, since it uses less digits than its factorization.

16403220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91144 (or 91139 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 16403220 is about 4050.0888879134. The cubic root of 16403220 is about 254.0834454167.

Adding to 16403220 its reverse (2230461), we get a palindrome (18633681).

The spelling of 16403220 in words is "sixteen million, four hundred three thousand, two hundred twenty".