21148764 has 96 divisors (see below), whose sum is σ = 61641216. Its totient is φ = 5495040.

The previous prime is 21148759. The next prime is 21148769. The reversal of 21148764 is 46784112.

It is an interprime number because it is at equal distance from previous prime (21148759) and next prime (21148769).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21148769) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 116754 + ... + 116934.

It is an arithmetic number, because the mean of its divisors is an integer number (642096).

Almost surely, 2^21148764 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 21148764, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30820608).

21148764 is an abundant number, since it is smaller than the sum of its proper divisors (40492452).

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

21148764 is a wasteful number, since it uses less digits than its factorization.

21148764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315 (or 313 counting only the distinct ones).

The product of its digits is 10752, while the sum is 33.

The square root of 21148764 is about 4598.7785334804. The cubic root of 21148764 is about 276.5423592789.

It can be divided in two parts, 21148 and 764, that added together give a palindrome (21912).

The spelling of 21148764 in words is "twenty-one million, one hundred forty-eight thousand, seven hundred sixty-four".