21500066 has 8 divisors (see below), whose sum is σ = 36857280. Its totient is φ = 9214308.

The previous prime is 21500029. The next prime is 21500069. The reversal of 21500066 is 66000512.

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

It is not an unprimeable number, because it can be changed into a prime (21500069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 767846 + ... + 767873.

It is an arithmetic number, because the mean of its divisors is an integer number (4607160).

Almost surely, 2^21500066 is an apocalyptic number.

21500066 is a deficient number, since it is larger than the sum of its proper divisors (15357214).

21500066 is a wasteful number, since it uses less digits than its factorization.

21500066 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1535728.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 21500066 is about 4636.8163647054. The cubic root of 21500066 is about 278.0651728573.

Adding to 21500066 its reverse (66000512), we get a palindrome (87500578).

The spelling of 21500066 in words is "twenty-one million, five hundred thousand, sixty-six".