21110645 has 8 divisors (see below), whose sum is σ = 25398360. Its totient is φ = 16844800.

The previous prime is 21110611. The next prime is 21110647. The reversal of 21110645 is 54601112.

It can be written as a sum of positive squares in 4 ways, for example, as 11519236 + 9591409 = 3394^2 + 3097^2 .

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

It is not a de Polignac number, because 21110645 - 2¹⁶ = 21045109 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21110647) by changing a digit.

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, 3260 + ... + 7269.

It is an arithmetic number, because the mean of its divisors is an integer number (3174795).

Almost surely, 2^21110645 is an apocalyptic number.

It is an amenable number.

21110645 is a deficient number, since it is larger than the sum of its proper divisors (4287715).

21110645 is a wasteful number, since it uses less digits than its factorization.

21110645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10935.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 21110645 is about 4594.6321942023. The cubic root of 21110645 is about 276.3761106672.

Adding to 21110645 its reverse (54601112), we get a palindrome (75711757).

The spelling of 21110645 in words is "twenty-one million, one hundred ten thousand, six hundred forty-five".