21127806 has 48 divisors (see below), whose sum is σ = 53056224. Its totient is φ = 5951232.

The previous prime is 21127783. The next prime is 21127817. The reversal of 21127806 is 60872112.

It is a self number, because there is not a number n which added to its sum of digits gives 21127806.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8050 + ... + 10346.

It is an arithmetic number, because the mean of its divisors is an integer number (1105338).

Almost surely, 2^21127806 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21127806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26528112).

21127806 is an abundant number, since it is smaller than the sum of its proper divisors (31928418).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21127806 is a wasteful number, since it uses less digits than its factorization.

21127806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2385 (or 2382 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 27.

The square root of 21127806 is about 4596.4993201348. The cubic root of 21127806 is about 276.4509797808.

Adding to 21127806 its reverse (60872112), we get a palindrome (81999918).

The spelling of 21127806 in words is "twenty-one million, one hundred twenty-seven thousand, eight hundred six".