21301604 has 6 divisors (see below), whose sum is σ = 37277814. Its totient is φ = 10650800.

The previous prime is 21301589. The next prime is 21301613. The reversal of 21301604 is 40610312.

It can be written as a sum of positive squares in only one way, i.e., 21141604 + 160000 = 4598^2 + 400^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2662697 + ... + 2662704.

It is an arithmetic number, because the mean of its divisors is an integer number (6212969).

Almost surely, 2^21301604 is an apocalyptic number.

It is an amenable number.

21301604 is a deficient number, since it is larger than the sum of its proper divisors (15976210).

21301604 is a wasteful number, since it uses less digits than its factorization.

21301604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5325405 (or 5325403 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 21301604 is about 4615.3660743217. The cubic root of 21301604 is about 277.2069421970.

Adding to 21301604 its reverse (40610312), we get a palindrome (61911916).

The spelling of 21301604 in words is "twenty-one million, three hundred one thousand, six hundred four".