21485128 has 48 divisors (see below), whose sum is σ = 48919680. Its totient is φ = 8803872.

The previous prime is 21485119. The next prime is 21485129. The reversal of 21485128 is 82158412.

It is a super-2 number, since 2×21485128² = 923221450352768, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21485128.

It is not an unprimeable number, because it can be changed into a prime (21485129) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7825 + ... + 10207.

It is an arithmetic number, because the mean of its divisors is an integer number (1019160).

Almost surely, 2^21485128 is an apocalyptic number.

21485128 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 21485128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24459840).

21485128 is an abundant number, since it is smaller than the sum of its proper divisors (27434552).

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

21485128 is a wasteful number, since it uses less digits than its factorization.

21485128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2426 (or 2415 counting only the distinct ones).

The product of its digits is 5120, while the sum is 31.

The square root of 21485128 is about 4635.2052813225. The cubic root of 21485128 is about 278.0007591029. Note that the first 3 decimals are identical.

The spelling of 21485128 in words is "twenty-one million, four hundred eighty-five thousand, one hundred twenty-eight".