21703680 has 176 divisors, whose sum is σ = 77622240. Its totient is φ = 5750784.

The previous prime is 21703667. The next prime is 21703699. The reversal of 21703680 is 8630712.

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 138162 + ... + 138318.

Almost surely, 2^21703680 is an apocalyptic number.

21703680 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 21703680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38811120).

21703680 is an abundant number, since it is smaller than the sum of its proper divisors (55918560).

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

21703680 is a wasteful number, since it uses less digits than its factorization.

21703680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 191 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 27.

The square root of 21703680 is about 4658.7208544836. The cubic root of 21703680 is about 278.9402114919.

The spelling of 21703680 in words is "twenty-one million, seven hundred three thousand, six hundred eighty".