16505220 has 24 divisors (see below), whose sum is σ = 46214784. Its totient is φ = 4401376.

The previous prime is 16505213. The next prime is 16505261. The reversal of 16505220 is 2250561.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 137484 + ... + 137603.

It is an arithmetic number, because the mean of its divisors is an integer number (1925616).

Almost surely, 2^16505220 is an apocalyptic number.

16505220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16505220 is an abundant number, since it is smaller than the sum of its proper divisors (29709564).

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

16505220 is a wasteful number, since it uses less digits than its factorization.

16505220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275099 (or 275097 counting only the distinct ones).

The product of its (nonzero) digits is 600, while the sum is 21.

The square root of 16505220 is about 4062.6616890900. The cubic root of 16505220 is about 254.6090124992.

Adding to 16505220 its reverse (2250561), we get a palindrome (18755781).

The spelling of 16505220 in words is "sixteen million, five hundred five thousand, two hundred twenty".