21740688 has 120 divisors (see below), whose sum is σ = 65808288. Its totient is φ = 6675456.

The previous prime is 21740687. The next prime is 21740711. The reversal of 21740688 is 88604712.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (21740683) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 203131 + ... + 203237.

Almost surely, 2^21740688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21740688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32904144).

21740688 is an abundant number, since it is smaller than the sum of its proper divisors (44067600).

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

21740688 is a wasteful number, since it uses less digits than its factorization.

21740688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221 (or 212 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 21740688 is about 4662.6910684711. The cubic root of 21740688 is about 279.0986663019.

The spelling of 21740688 in words is "twenty-one million, seven hundred forty thousand, six hundred eighty-eight".