21152005 has 8 divisors (see below), whose sum is σ = 29008512. Its totient is φ = 14504208.

The previous prime is 21152003. The next prime is 21152009. The reversal of 21152005 is 50025112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21152005 - 2¹ = 21152003 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21152005.

It is a congruent number.

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

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 302137 + ... + 302206.

It is an arithmetic number, because the mean of its divisors is an integer number (3626064).

Almost surely, 2^21152005 is an apocalyptic number.

It is an amenable number.

21152005 is a deficient number, since it is larger than the sum of its proper divisors (7856507).

21152005 is an equidigital number, since it uses as much as digits as its factorization.

21152005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 604355.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 21152005 is about 4599.1308961585. The cubic root of 21152005 is about 276.5564850533.

Adding to 21152005 its reverse (50025112), we get a palindrome (71177117).

The spelling of 21152005 in words is "twenty-one million, one hundred fifty-two thousand, five".