21152004 has 24 divisors (see below), whose sum is σ = 49465920. Its totient is φ = 7034784.

The previous prime is 21152003. The next prime is 21152009. The reversal of 21152004 is 40025112.

It is not an unprimeable number, because it can be changed into a prime (21152003) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4377 + ... + 7839.

It is an arithmetic number, because the mean of its divisors is an integer number (2061080).

Almost surely, 2^21152004 is an apocalyptic number.

It is an amenable number.

21152004 is an abundant number, since it is smaller than the sum of its proper divisors (28313916).

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

21152004 is a wasteful number, since it uses less digits than its factorization.

21152004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3979 (or 3977 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21152004 is about 4599.1307874423. The cubic root of 21152004 is about 276.5564806951.

Adding to 21152004 its reverse (40025112), we get a palindrome (61177116).

The spelling of 21152004 in words is "twenty-one million, one hundred fifty-two thousand, four".