21380515 has 8 divisors (see below), whose sum is σ = 27630288. Its totient is φ = 15788640.

The previous prime is 21380473. The next prime is 21380519. The reversal of 21380515 is 51508312.

It is a happy number.

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

It is not a de Polignac number, because 21380515 - 2¹⁷ = 21249443 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 21380515.

It is not an unprimeable number, because it can be changed into a prime (21380519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 164401 + ... + 164530.

It is an arithmetic number, because the mean of its divisors is an integer number (3453786).

Almost surely, 2^21380515 is an apocalyptic number.

21380515 is a deficient number, since it is larger than the sum of its proper divisors (6249773).

21380515 is a wasteful number, since it uses less digits than its factorization.

It is an anagram of its base 11 representation: 21380515 = (11083552)₁₁.

21380515 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328949.

The product of its (nonzero) digits is 1200, while the sum is 25.

The square root of 21380515 is about 4623.9068978516. The cubic root of 21380515 is about 277.5488213212.

Adding to 21380515 its reverse (51508312), we get a palindrome (72888827).

The spelling of 21380515 in words is "twenty-one million, three hundred eighty thousand, five hundred fifteen".