21321048 has 64 divisors (see below), whose sum is σ = 61344000. Its totient is φ = 6049152.

The previous prime is 21321031. The next prime is 21321067. The reversal of 21321048 is 84012312.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a plaindrome in base 16.

It is a congruent number.

It is an unprimeable number.

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, 29718 + ... + 30426.

It is an arithmetic number, because the mean of its divisors is an integer number (958500).

Almost surely, 2^21321048 is an apocalyptic number.

21321048 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 21321048, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30672000).

21321048 is an abundant number, since it is smaller than the sum of its proper divisors (40022952).

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

21321048 is a wasteful number, since it uses less digits than its factorization.

21321048 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 904 (or 900 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21321048 is about 4617.4720356489. The cubic root of 21321048 is about 277.2912609275.

The spelling of 21321048 in words is "twenty-one million, three hundred twenty-one thousand, forty-eight".