21051704 has 16 divisors (see below), whose sum is σ = 39916800. Its totient is φ = 10407232.

The previous prime is 21051703. The next prime is 21051707. The reversal of 21051704 is 40715012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051703) 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, 14072 + ... + 15495.

It is an arithmetic number, because the mean of its divisors is an integer number (2494800).

Almost surely, 2^21051704 is an apocalyptic number.

It is an amenable number.

21051704 is a deficient number, since it is larger than the sum of its proper divisors (18865096).

21051704 is a wasteful number, since it uses less digits than its factorization.

21051704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29662 (or 29658 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 21051704 is about 4588.2135957255. The cubic root of 21051704 is about 276.1186565349.

Adding to 21051704 its reverse (40715012), we get a palindrome (61766716).

The spelling of 21051704 in words is "twenty-one million, fifty-one thousand, seven hundred four".