21394128 has 80 divisors (see below), whose sum is σ = 64745856. Its totient is φ = 5959680.

The previous prime is 21394127. The next prime is 21394151. The reversal of 21394128 is 82149312.

It is a junction number, because it is equal to n+sod(n) for n = 21394095 and 21394104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21394127) 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 15 ways as a sum of consecutive naturals, for example, 13000 + ... + 14552.

Almost surely, 2^21394128 is an apocalyptic number.

21394128 is a gapful number since it is divisible by the number (28) 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 21394128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32372928).

21394128 is an abundant number, since it is smaller than the sum of its proper divisors (43351728).

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

21394128 is a wasteful number, since it uses less digits than its factorization.

21394128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1612 (or 1606 counting only the distinct ones).

The product of its digits is 3456, while the sum is 30.

The square root of 21394128 is about 4625.3786871996. The cubic root of 21394128 is about 277.6077140484.

The spelling of 21394128 in words is "twenty-one million, three hundred ninety-four thousand, one hundred twenty-eight".