21110066 has 4 divisors (see below), whose sum is σ = 31665102. Its totient is φ = 10555032.

The previous prime is 21110051. The next prime is 21110071. The reversal of 21110066 is 66001112.

It is a happy number.

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

It can be written as a sum of positive squares in only one way, i.e., 16362025 + 4748041 = 4045^2 + 2179^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5277515 + ... + 5277518.

Almost surely, 2^21110066 is an apocalyptic number.

21110066 is a deficient number, since it is larger than the sum of its proper divisors (10555036).

21110066 is a wasteful number, since it uses less digits than its factorization.

21110066 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10555035.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 21110066 is about 4594.5691854623. The cubic root of 21110066 is about 276.3735839288.

Adding to 21110066 its reverse (66001112), we get a palindrome (87111178).

The spelling of 21110066 in words is "twenty-one million, one hundred ten thousand, sixty-six".