21152504 has 8 divisors (see below), whose sum is σ = 39660960. Its totient is φ = 10576248.

The previous prime is 21152477. The next prime is 21152507. The reversal of 21152504 is 40525112.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152507) 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 as a sum of consecutive naturals, namely, 1322024 + ... + 1322039.

It is an arithmetic number, because the mean of its divisors is an integer number (4957620).

Almost surely, 2^21152504 is an apocalyptic number.

It is an amenable number.

21152504 is a deficient number, since it is larger than the sum of its proper divisors (18508456).

21152504 is a wasteful number, since it uses less digits than its factorization.

21152504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2644069 (or 2644065 counting only the distinct ones).

The product of its (nonzero) digits is 400, while the sum is 20.

The square root of 21152504 is about 4599.1851452187. The cubic root of 21152504 is about 276.5586597975.

Adding to 21152504 its reverse (40525112), we get a palindrome (61677616).

The spelling of 21152504 in words is "twenty-one million, one hundred fifty-two thousand, five hundred four".