21260066 has 8 divisors (see below), whose sum is σ = 31943964. Its totient is φ = 10612080.

The previous prime is 21260051. The next prime is 21260077. The reversal of 21260066 is 66006212.

It can be written as a sum of positive squares in 2 ways, for example, as 20894041 + 366025 = 4571^2 + 605^2 .

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

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7445 + ... + 9896.

Almost surely, 2^21260066 is an apocalyptic number.

21260066 is a deficient number, since it is larger than the sum of its proper divisors (10683898).

21260066 is a wasteful number, since it uses less digits than its factorization.

21260066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17956.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21260066 is about 4610.8639103751. The cubic root of 21260066 is about 277.0266409927.

Adding to 21260066 its reverse (66006212), we get a palindrome (87266278).

The spelling of 21260066 in words is "twenty-one million, two hundred sixty thousand, sixty-six".