16509420 has 144 divisors (see below), whose sum is σ = 53813760. Its totient is φ = 4245696.

The previous prime is 16509419. The next prime is 16509421. The reversal of 16509420 is 2490561.

16509420 is a `hidden beast` number, since 1 + 650 + 9 + 4 + 2 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (16509419) and next prime (16509421).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16509421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 208941 + ... + 209019.

Almost surely, 2^16509420 is an apocalyptic number.

16509420 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16509420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26906880).

16509420 is an abundant number, since it is smaller than the sum of its proper divisors (37304340).

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

16509420 is a wasteful number, since it uses less digits than its factorization.

16509420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146 (or 132 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 16509420 is about 4063.1785587148. The cubic root of 16509420 is about 254.6306070243.

Adding to 16509420 its reverse (2490561), we get a palindrome (18999981).

The spelling of 16509420 in words is "sixteen million, five hundred nine thousand, four hundred twenty".