21051304 has 16 divisors (see below), whose sum is σ = 41793300. Its totient is φ = 9906432.

The previous prime is 21051271. The next prime is 21051311. The reversal of 21051304 is 40315012.

It can be written as a sum of positive squares in 2 ways, for example, as 19096900 + 1954404 = 4370^2 + 1398^2 .

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 77259 + ... + 77530.

Almost surely, 2^21051304 is an apocalyptic number.

It is an amenable number.

21051304 is a deficient number, since it is larger than the sum of its proper divisors (20741996).

21051304 is a wasteful number, since it uses less digits than its factorization.

21051304 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154812 (or 154808 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21051304 is about 4588.1700055687. The cubic root of 21051304 is about 276.1169076953.

Adding to 21051304 its reverse (40315012), we get a palindrome (61366316).

The spelling of 21051304 in words is "twenty-one million, fifty-one thousand, three hundred four".