21065347 has 4 divisors (see below), whose sum is σ = 21251880. Its totient is φ = 20878816.

The previous prime is 21065333. The next prime is 21065351. The reversal of 21065347 is 74356012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21065347 - 2¹⁵ = 21032579 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21065377) 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, 93097 + ... + 93322.

It is an arithmetic number, because the mean of its divisors is an integer number (5312970).

Almost surely, 2^21065347 is an apocalyptic number.

21065347 is a deficient number, since it is larger than the sum of its proper divisors (186533).

21065347 is a wasteful number, since it uses less digits than its factorization.

21065347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186532.

The product of its (nonzero) digits is 5040, while the sum is 28.

The square root of 21065347 is about 4589.7000991350. The cubic root of 21065347 is about 276.1782918237.

It can be divided in two parts, 21065 and 347, that added together give a palindrome (21412).

The spelling of 21065347 in words is "twenty-one million, sixty-five thousand, three hundred forty-seven".