21067505 has 8 divisors (see below), whose sum is σ = 26768232. Its totient is φ = 15862528.

The previous prime is 21067499. The next prime is 21067513. The reversal of 21067505 is 50576012.

It can be written as a sum of positive squares in 4 ways, for example, as 1495729 + 19571776 = 1223^2 + 4424^2 .

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 21067505 - 2⁶ = 21067441 is a prime.

It is a Duffinian number.

It is an unprimeable number.

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, 123842 + ... + 124011.

It is an arithmetic number, because the mean of its divisors is an integer number (3346029).

Almost surely, 2^21067505 is an apocalyptic number.

It is an amenable number.

21067505 is a deficient number, since it is larger than the sum of its proper divisors (5700727).

21067505 is a wasteful number, since it uses less digits than its factorization.

21067505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247875.

The product of its (nonzero) digits is 2100, while the sum is 26.

The square root of 21067505 is about 4589.9351847276. The cubic root of 21067505 is about 276.1877223576.

The spelling of 21067505 in words is "twenty-one million, sixty-seven thousand, five hundred five".