21313415 has 4 divisors (see below), whose sum is σ = 25576104. Its totient is φ = 17050728.

The previous prime is 21313379. The next prime is 21313429. The reversal of 21313415 is 51431312.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21313415 - 2¹² = 21309319 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 2131337 + ... + 2131346.

It is an arithmetic number, because the mean of its divisors is an integer number (6394026).

Almost surely, 2^21313415 is an apocalyptic number.

21313415 is a deficient number, since it is larger than the sum of its proper divisors (4262689).

21313415 is an equidigital number, since it uses as much as digits as its factorization.

21313415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4262688.

The product of its digits is 360, while the sum is 20.

The square root of 21313415 is about 4616.6454271473. The cubic root of 21313415 is about 277.2581666065.

Adding to 21313415 its reverse (51431312), we get a palindrome (72744727).

The spelling of 21313415 in words is "twenty-one million, three hundred thirteen thousand, four hundred fifteen".