16621920 has 288 divisors, whose sum is σ = 69346368. Its totient is φ = 3538944.

The previous prime is 16621897. The next prime is 16621949. The reversal of 16621920 is 2912661.

16621920 is a `hidden beast` number, since 16 + 621 + 9 + 20 = 666.

16621920 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (288).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 171312 + ... + 171408.

It is an arithmetic number, because the mean of its divisors is an integer number (240786).

Almost surely, 2^16621920 is an apocalyptic number.

16621920 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 16621920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34673184).

16621920 is an abundant number, since it is smaller than the sum of its proper divisors (52724448).

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

16621920 is a wasteful number, since it uses less digits than its factorization.

16621920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142 (or 131 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 16621920 is about 4076.9988962471. The cubic root of 16621920 is about 255.2076739601.

The spelling of 16621920 in words is "sixteen million, six hundred twenty-one thousand, nine hundred twenty".