21101663 has 8 divisors (see below), whose sum is σ = 23123280. Its totient is φ = 19097280.

The previous prime is 21101651. The next prime is 21101677. The reversal of 21101663 is 36610112.

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 21101663 - 2⁸ = 21101407 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101683) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1670 + ... + 6707.

It is an arithmetic number, because the mean of its divisors is an integer number (2890410).

Almost surely, 2^21101663 is an apocalyptic number.

21101663 is a deficient number, since it is larger than the sum of its proper divisors (2021617).

21101663 is a wasteful number, since it uses less digits than its factorization.

21101663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8617.

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 21101663 is about 4593.6546452688. The cubic root of 21101663 is about 276.3369082905.

Adding to 21101663 its reverse (36610112), we get a palindrome (57711775).

It can be divided in two parts, 2110 and 1663, that added together give a palindrome (3773).

The spelling of 21101663 in words is "twenty-one million, one hundred one thousand, six hundred sixty-three".