21152517 has 8 divisors (see below), whose sum is σ = 28859424. Its totient is φ = 13773648.

The previous prime is 21152507. The next prime is 21152519. The reversal of 21152517 is 71525112.

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

It is not a de Polignac number, because 21152517 - 2¹⁴ = 21136133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152519) 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, 81858 + ... + 82115.

It is an arithmetic number, because the mean of its divisors is an integer number (3607428).

Almost surely, 2^21152517 is an apocalyptic number.

It is an amenable number.

21152517 is a deficient number, since it is larger than the sum of its proper divisors (7706907).

21152517 is a wasteful number, since it uses less digits than its factorization.

21152517 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164019.

The product of its digits is 700, while the sum is 24.

The square root of 21152517 is about 4599.1865585123. The cubic root of 21152517 is about 276.5587164537.

Adding to 21152517 its reverse (71525112), we get a palindrome (92677629).

The spelling of 21152517 in words is "twenty-one million, one hundred fifty-two thousand, five hundred seventeen".