21127813 has 8 divisors (see below), whose sum is σ = 24225728. Its totient is φ = 18049824.

The previous prime is 21127783. The next prime is 21127817. The reversal of 21127813 is 31872112.

It is a happy number.

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 21127813 - 2⁵ = 21127781 is a prime.

It is the 4597-th Hogben number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21127817) by changing a digit.

It is a nontrivial repunit in base 4596.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2631 + ... + 7012.

It is an arithmetic number, because the mean of its divisors is an integer number (3028216).

Almost surely, 2^21127813 is an apocalyptic number.

It is an amenable number.

21127813 is a deficient number, since it is larger than the sum of its proper divisors (3097915).

21127813 is an equidigital number, since it uses as much as digits as its factorization.

21127813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9963.

The product of its digits is 672, while the sum is 25.

The square root of 21127813 is about 4596.5000815838. The cubic root of 21127813 is about 276.4510103118.

Adding to 21127813 its reverse (31872112), we get a palindrome (52999925).

The spelling of 21127813 in words is "twenty-one million, one hundred twenty-seven thousand, eight hundred thirteen".