21706480 has 80 divisors (see below), whose sum is σ = 53996544. Its totient is φ = 8096000.

The previous prime is 21706463. The next prime is 21706519. The reversal of 21706480 is 8460712.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 86355 + ... + 86605.

Almost surely, 2^21706480 is an apocalyptic number.

21706480 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 21706480, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26998272).

21706480 is an abundant number, since it is smaller than the sum of its proper divisors (32290064).

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

21706480 is a wasteful number, since it uses less digits than its factorization.

21706480 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 334 (or 328 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 21706480 is about 4659.0213564653. The cubic root of 21706480 is about 278.9522063703.

The spelling of 21706480 in words is "twenty-one million, seven hundred six thousand, four hundred eighty".