21003704 has 16 divisors (see below), whose sum is σ = 41698800. Its totient is φ = 9884032.

The previous prime is 21003677. The next prime is 21003707. The reversal of 21003704 is 40730012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21003707) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77084 + ... + 77355.

It is an arithmetic number, because the mean of its divisors is an integer number (2606175).

Almost surely, 2^21003704 is an apocalyptic number.

It is an amenable number.

21003704 is a deficient number, since it is larger than the sum of its proper divisors (20695096).

21003704 is a wasteful number, since it uses less digits than its factorization.

21003704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154462 (or 154458 counting only the distinct ones).

The product of its (nonzero) digits is 168, while the sum is 17.

The square root of 21003704 is about 4582.9798166695. The cubic root of 21003704 is about 275.9086374070.

Adding to 21003704 its reverse (40730012), we get a palindrome (61733716).

The spelling of 21003704 in words is "twenty-one million, three thousand, seven hundred four".