21304047 has 8 divisors (see below), whose sum is σ = 28805760. Its totient is φ = 14002520.

The previous prime is 21304027. The next prime is 21304061. The reversal of 21304047 is 74040312.

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 21304047 - 2²³ = 12915439 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21304027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49797 + ... + 50222.

It is an arithmetic number, because the mean of its divisors is an integer number (3600720).

Almost surely, 2^21304047 is an apocalyptic number.

21304047 is a deficient number, since it is larger than the sum of its proper divisors (7501713).

21304047 is a wasteful number, since it uses less digits than its factorization.

21304047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100093.

The product of its (nonzero) digits is 672, while the sum is 21.

The square root of 21304047 is about 4615.6307261305. The cubic root of 21304047 is about 277.2175390621.

Adding to 21304047 its reverse (74040312), we get a palindrome (95344359).

The spelling of 21304047 in words is "twenty-one million, three hundred four thousand, forty-seven".