21254128 has 40 divisors (see below), whose sum is σ = 47521760. Its totient is φ = 9020160.

The previous prime is 21254119. The next prime is 21254143. The reversal of 21254128 is 82145212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11338 + ... + 13078.

It is an arithmetic number, because the mean of its divisors is an integer number (1188044).

Almost surely, 2^21254128 is an apocalyptic number.

21254128 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 21254128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23760880).

21254128 is an abundant number, since it is smaller than the sum of its proper divisors (26267632).

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

21254128 is a wasteful number, since it uses less digits than its factorization.

21254128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1865 (or 1859 counting only the distinct ones).

The product of its digits is 1280, while the sum is 25.

The square root of 21254128 is about 4610.2199513689. The cubic root of 21254128 is about 277.0008471347. Note that the first 3 decimals are identical.

The spelling of 21254128 in words is "twenty-one million, two hundred fifty-four thousand, one hundred twenty-eight".