21090048 has 72 divisors (see below), whose sum is σ = 64165248. Its totient is φ = 6024192.

The previous prime is 21090007. The next prime is 21090061. The reversal of 21090048 is 84009012.

It is a Harshad number since it is a multiple of its sum of digits (24).

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, 3415 + ... + 7337.

It is an arithmetic number, because the mean of its divisors is an integer number (891184).

Almost surely, 2^21090048 is an apocalyptic number.

21090048 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 21090048, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32082624).

21090048 is an abundant number, since it is smaller than the sum of its proper divisors (43075200).

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

21090048 is an equidigital number, since it uses as much as digits as its factorization.

21090048 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3949 (or 3935 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 24.

The square root of 21090048 is about 4592.3902273217. The cubic root of 21090048 is about 276.2861975595.

It can be divided in two parts, 2109004 and 8, that added together give a palindrome (2109012).

The spelling of 21090048 in words is "twenty-one million, ninety thousand, forty-eight".