21394560 has 128 divisors (see below), whose sum is σ = 74468160. Its totient is φ = 5181440.

The previous prime is 21394519. The next prime is 21394561. The reversal of 21394560 is 6549312.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a zygodrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21394561) 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, 20614 + ... + 21626.

Almost surely, 2^21394560 is an apocalyptic number.

21394560 is a gapful number since it is divisible by the number (20) 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 21394560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37234080).

21394560 is an abundant number, since it is smaller than the sum of its proper divisors (53073600).

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

21394560 is a wasteful number, since it uses less digits than its factorization.

21394560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1046 (or 1034 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 21394560 is about 4625.4253858429. The cubic root of 21394560 is about 277.6095825631.

The spelling of 21394560 in words is "twenty-one million, three hundred ninety-four thousand, five hundred sixty".