21704250 has 64 divisors (see below), whose sum is σ = 55516032. Its totient is φ = 5644800.

The previous prime is 21704233. The next prime is 21704261. The reversal of 21704250 is 5240712.

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 31 ways as a sum of consecutive naturals, for example, 31914 + ... + 32586.

It is an arithmetic number, because the mean of its divisors is an integer number (867438).

Almost surely, 2^21704250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21704250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27758016).

21704250 is an abundant number, since it is smaller than the sum of its proper divisors (33811782).

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

21704250 is a wasteful number, since it uses less digits than its factorization.

21704250 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 736 (or 726 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 21.

The square root of 21704250 is about 4658.7820296726. The cubic root of 21704250 is about 278.9426533900.

Adding to 21704250 its reverse (5240712), we get a palindrome (26944962).

The spelling of 21704250 in words is "twenty-one million, seven hundred four thousand, two hundred fifty".