21439680 has 112 divisors (see below), whose sum is σ = 71103744. Its totient is φ = 5463040.

The previous prime is 21439673. The next prime is 21439699. The reversal of 21439680 is 8693412.

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, 21595 + ... + 22565.

Almost surely, 2^21439680 is an apocalyptic number.

21439680 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 21439680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35551872).

21439680 is an abundant number, since it is smaller than the sum of its proper divisors (49664064).

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

21439680 is a wasteful number, since it uses less digits than its factorization.

21439680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1014 (or 1004 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 21439680 is about 4630.3002062501. The cubic root of 21439680 is about 277.8046001951.

The spelling of 21439680 in words is "twenty-one million, four hundred thirty-nine thousand, six hundred eighty".