21380352 has 144 divisors (see below), whose sum is σ = 67304832. Its totient is φ = 5898240.

The previous prime is 21380341. The next prime is 21380369. The reversal of 21380352 is 25308312.

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 15 ways as a sum of consecutive naturals, for example, 220368 + ... + 220464.

Almost surely, 2^21380352 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21380352, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33652416).

21380352 is an abundant number, since it is smaller than the sum of its proper divisors (45924480).

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

21380352 is an equidigital number, since it uses as much as digits as its factorization.

21380352 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164 (or 150 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21380352 is about 4623.8892720306. The cubic root of 21380352 is about 277.5481159972.

Adding to 21380352 its reverse (25308312), we get a palindrome (46688664).

The spelling of 21380352 in words is "twenty-one million, three hundred eighty thousand, three hundred fifty-two".