21004715 has 8 divisors (see below), whose sum is σ = 25887120. Its totient is φ = 16349472.

The previous prime is 21004691. The next prime is 21004721. The reversal of 21004715 is 51740012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21004715 - 2⁶ = 21004651 is a prime.

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, 56585 + ... + 56954.

It is an arithmetic number, because the mean of its divisors is an integer number (3235890).

Almost surely, 2^21004715 is an apocalyptic number.

21004715 is a deficient number, since it is larger than the sum of its proper divisors (4882405).

21004715 is a wasteful number, since it uses less digits than its factorization.

21004715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113581.

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

The square root of 21004715 is about 4583.0901147588. The cubic root of 21004715 is about 275.9130642318.

Adding to 21004715 its reverse (51740012), we get a palindrome (72744727).

The spelling of 21004715 in words is "twenty-one million, four thousand, seven hundred fifteen".