21165413 has 4 divisors (see below), whose sum is σ = 21292320. Its totient is φ = 21038508.

The previous prime is 21165409. The next prime is 21165421. The reversal of 21165413 is 31456112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21165413 - 2² = 21165409 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21167413) 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 3 ways as a sum of consecutive naturals, for example, 63203 + ... + 63536.

It is an arithmetic number, because the mean of its divisors is an integer number (5323080).

Almost surely, 2^21165413 is an apocalyptic number.

It is an amenable number.

21165413 is a deficient number, since it is larger than the sum of its proper divisors (126907).

21165413 is a wasteful number, since it uses less digits than its factorization.

21165413 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126906.

The product of its digits is 720, while the sum is 23.

The square root of 21165413 is about 4600.5883319419. The cubic root of 21165413 is about 276.6149079802.

The spelling of 21165413 in words is "twenty-one million, one hundred sixty-five thousand, four hundred thirteen".