21453764 has 12 divisors (see below), whose sum is σ = 38252844. Its totient is φ = 10524384.

The previous prime is 21453763. The next prime is 21453769. The reversal of 21453764 is 46735412.

It can be written as a sum of positive squares in 2 ways, for example, as 17572864 + 3880900 = 4192^2 + 1970^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21453764.

It is not an unprimeable number, because it can be changed into a prime (21453763) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50387 + ... + 50810.

It is an arithmetic number, because the mean of its divisors is an integer number (3187737).

Almost surely, 2^21453764 is an apocalyptic number.

It is an amenable number.

21453764 is a deficient number, since it is larger than the sum of its proper divisors (16799080).

21453764 is a wasteful number, since it uses less digits than its factorization.

21453764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101254 (or 101252 counting only the distinct ones).

The product of its digits is 20160, while the sum is 32.

The square root of 21453764 is about 4631.8208082783. The cubic root of 21453764 is about 277.8654180114.

The spelling of 21453764 in words is "twenty-one million, four hundred fifty-three thousand, seven hundred sixty-four".