21380832 has 144 divisors (see below), whose sum is σ = 70407792. Its totient is φ = 6082560.

The previous prime is 21380813. The next prime is 21380851. The reversal of 21380832 is 23808312.

It is an interprime number because it is at equal distance from previous prime (21380813) and next prime (21380851).

It is a tau number, because it is divible by the number of its divisors (144).

It is a junction number, because it is equal to n+sod(n) for n = 21380796 and 21380805.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 53658 + ... + 54054.

It is an arithmetic number, because the mean of its divisors is an integer number (488943).

Almost surely, 2^21380832 is an apocalyptic number.

21380832 is a gapful number since it is divisible by the number (22) 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 21380832, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35203896).

21380832 is an abundant number, since it is smaller than the sum of its proper divisors (49026960).

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

21380832 is a wasteful number, since it uses less digits than its factorization.

21380832 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 441 (or 430 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 21380832 is about 4623.9411760964. The cubic root of 21380832 is about 277.5501930147.

The spelling of 21380832 in words is "twenty-one million, three hundred eighty thousand, eight hundred thirty-two".