21030911 has 8 divisors (see below), whose sum is σ = 23563344. Its totient is φ = 18601920.

The previous prime is 21030899. The next prime is 21030923. The reversal of 21030911 is 11903012.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21030899) and next prime (21030923).

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 21030911 - 2¹⁴ = 21014527 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21030911.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21030931) 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, 25430 + ... + 26243.

It is an arithmetic number, because the mean of its divisors is an integer number (2945418).

Almost surely, 2^21030911 is an apocalyptic number.

21030911 is a deficient number, since it is larger than the sum of its proper divisors (2532433).

21030911 is a wasteful number, since it uses less digits than its factorization.

21030911 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51721.

The product of its (nonzero) digits is 54, while the sum is 17.

The square root of 21030911 is about 4585.9471213698. The cubic root of 21030911 is about 276.0277181082.

Adding to 21030911 its reverse (11903012), we get a palindrome (32933923).

The spelling of 21030911 in words is "twenty-one million, thirty thousand, nine hundred eleven".