21507704 has 16 divisors (see below), whose sum is σ = 40646400. Its totient is φ = 10668672.

The previous prime is 21507701. The next prime is 21507709. The reversal of 21507704 is 40770512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21507701) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9569 + ... + 11600.

It is an arithmetic number, because the mean of its divisors is an integer number (2540400).

Almost surely, 2^21507704 is an apocalyptic number.

It is an amenable number.

21507704 is a deficient number, since it is larger than the sum of its proper divisors (19138696).

21507704 is a wasteful number, since it uses less digits than its factorization.

21507704 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21302 (or 21298 counting only the distinct ones).

The product of its (nonzero) digits is 1960, while the sum is 26.

The square root of 21507704 is about 4637.6399170268. The cubic root of 21507704 is about 278.0980969475.

The spelling of 21507704 in words is "twenty-one million, five hundred seven thousand, seven hundred four".