16921440 has 96 divisors (see below), whose sum is σ = 59240160. Its totient is φ = 4511232.

The previous prime is 16921427. The next prime is 16921447. The reversal of 16921440 is 4412961.

It is a tau number, because it is divible by the number of its divisors (96).

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 (16921447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2362 + ... + 6278.

It is an arithmetic number, because the mean of its divisors is an integer number (617085).

Almost surely, 2^16921440 is an apocalyptic number.

16921440 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 16921440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29620080).

16921440 is an abundant number, since it is smaller than the sum of its proper divisors (42318720).

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

16921440 is a wasteful number, since it uses less digits than its factorization.

16921440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3941 (or 3927 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 16921440 is about 4113.5677945064. The cubic root of 16921440 is about 256.7314691793.

It can be divided in two parts, 169 and 21440, that added together give a square (21609 = 147²).

The spelling of 16921440 in words is "sixteen million, nine hundred twenty-one thousand, four hundred forty".