16621648 has 40 divisors (see below), whose sum is σ = 34772328. Its totient is φ = 7667712.

The previous prime is 16621643. The next prime is 16621681. The reversal of 16621648 is 84612661.

It can be written as a sum of positive squares in 4 ways, for example, as 8714304 + 7907344 = 2952^2 + 2812^2 .

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16621643) 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 7 ways as a sum of consecutive naturals, for example, 13840 + ... + 14992.

Almost surely, 2^16621648 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 16621648, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (17386164).

16621648 is an abundant number, since it is smaller than the sum of its proper divisors (18150680).

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

16621648 is a wasteful number, since it uses less digits than its factorization.

16621648 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1231 (or 1225 counting only the distinct ones).

The product of its digits is 13824, while the sum is 34.

The square root of 16621648 is about 4076.9655382404. The cubic root of 16621648 is about 255.2062818853.

The spelling of 16621648 in words is "sixteen million, six hundred twenty-one thousand, six hundred forty-eight".