21126464 has 28 divisors (see below), whose sum is σ = 42405300. Its totient is φ = 10441728.

The previous prime is 21126463. The next prime is 21126467. The reversal of 21126464 is 46462112.

It can be written as a sum of positive squares in 2 ways, for example, as 4804864 + 16321600 = 2192^2 + 4040^2 .

It is a super-2 number, since 2×21126464² = 892654962286592, which contains 22 as substring.

21126464 is a modest number, since divided by 6464 gives 2112 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126463) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3842 + ... + 7550.

It is an arithmetic number, because the mean of its divisors is an integer number (1514475).

Almost surely, 2^21126464 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21126464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21202650).

21126464 is an abundant number, since it is smaller than the sum of its proper divisors (21278836).

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

21126464 is an equidigital number, since it uses as much as digits as its factorization.

21126464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3810 (or 3800 counting only the distinct ones).

The product of its digits is 2304, while the sum is 26.

The square root of 21126464 is about 4596.3533371576. The cubic root of 21126464 is about 276.4451264349.

Adding to 21126464 its reverse (46462112), we get a palindrome (67588576).

The spelling of 21126464 in words is "twenty-one million, one hundred twenty-six thousand, four hundred sixty-four".