16521540 has 96 divisors (see below), whose sum is σ = 53437440. Its totient is φ = 3735936.

The previous prime is 16521529. The next prime is 16521541. The reversal of 16521540 is 4512561.

It is a super-2 number, since 2×16521540² = 545922567943200, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 16521540.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16521541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 58239 + ... + 58521.

It is an arithmetic number, because the mean of its divisors is an integer number (556640).

Almost surely, 2^16521540 is an apocalyptic number.

16521540 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 16521540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26718720).

16521540 is an abundant number, since it is smaller than the sum of its proper divisors (36915900).

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

16521540 is a wasteful number, since it uses less digits than its factorization.

16521540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441 (or 439 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

The square root of 16521540 is about 4064.6697282805. The cubic root of 16521540 is about 254.6929021274.

The spelling of 16521540 in words is "sixteen million, five hundred twenty-one thousand, five hundred forty".