21704242 has 16 divisors (see below), whose sum is σ = 37910592. Its totient is φ = 9126000.

The previous prime is 21704233. The next prime is 21704261. The reversal of 21704242 is 24240712.

It is a happy number.

21704242 is a modest number, since divided by 4242 gives 2170 as remainder.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13884 + ... + 15367.

It is an arithmetic number, because the mean of its divisors is an integer number (2369412).

Almost surely, 2^21704242 is an apocalyptic number.

21704242 is a deficient number, since it is larger than the sum of its proper divisors (16206350).

21704242 is a wasteful number, since it uses less digits than its factorization.

21704242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29313.

The product of its (nonzero) digits is 896, while the sum is 22.

The square root of 21704242 is about 4658.7811710790. The cubic root of 21704242 is about 278.9426191181.

Adding to 21704242 its reverse (24240712), we get a palindrome (45944954).

The spelling of 21704242 in words is "twenty-one million, seven hundred four thousand, two hundred forty-two".