21880320 has 320 divisors, whose sum is σ = 89565696. Its totient is φ = 4423680.

The previous prime is 21880319. The next prime is 21880321. The reversal of 21880320 is 2308812.

It is an interprime number because it is at equal distance from previous prime (21880319) and next prime (21880321).

It is a tau number, because it is divible by the number of its divisors (320).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21880321) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 591342 + ... + 591378.

Almost surely, 2^21880320 is an apocalyptic number.

21880320 is a gapful number since it is divisible by the number (20) 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 21880320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44782848).

21880320 is an abundant number, since it is smaller than the sum of its proper divisors (67685376).

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

21880320 is a wasteful number, since it uses less digits than its factorization.

21880320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81 (or 65 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The square root of 21880320 is about 4677.6404308155. The cubic root of 21880320 is about 279.6949057785.

The spelling of 21880320 in words is "twenty-one million, eight hundred eighty thousand, three hundred twenty".