21070505 has 8 divisors (see below), whose sum is σ = 25353600. Its totient is φ = 16810416.

The previous prime is 21070481. The next prime is 21070513. The reversal of 21070505 is 50507012.

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 21070505 - 2²² = 16876201 is a prime.

It is an alternating number because its digits alternate between even and odd.

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, 3665 + ... + 7454.

It is an arithmetic number, because the mean of its divisors is an integer number (3169200).

Almost surely, 2^21070505 is an apocalyptic number.

It is an amenable number.

21070505 is a deficient number, since it is larger than the sum of its proper divisors (4283095).

21070505 is a wasteful number, since it uses less digits than its factorization.

21070505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11503.

The product of its (nonzero) digits is 350, while the sum is 20.

The square root of 21070505 is about 4590.2619750947. The cubic root of 21070505 is about 276.2008313903.

Adding to 21070505 its reverse (50507012), we get a palindrome (71577517).

The spelling of 21070505 in words is "twenty-one million, seventy thousand, five hundred five".