16557220 has 24 divisors (see below), whose sum is σ = 34998264. Its totient is φ = 6579456.

The previous prime is 16557199. The next prime is 16557223. The reversal of 16557220 is 2275561.

16557220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 732736 + 15824484 = 856^2 + 3978^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16557223) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 504 + ... + 5776.

It is an arithmetic number, because the mean of its divisors is an integer number (1458261).

Almost surely, 2^16557220 is an apocalyptic number.

16557220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16557220 is an abundant number, since it is smaller than the sum of its proper divisors (18441044).

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

16557220 is a wasteful number, since it uses less digits than its factorization.

16557220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5439 (or 5437 counting only the distinct ones).

The product of its (nonzero) digits is 4200, while the sum is 28.

The square root of 16557220 is about 4069.0564016735. The cubic root of 16557220 is about 254.8761156539.

The spelling of 16557220 in words is "sixteen million, five hundred fifty-seven thousand, two hundred twenty".