21321415 has 8 divisors (see below), whose sum is σ = 25661520. Its totient is φ = 17006592.

The previous prime is 21321407. The next prime is 21321431. The reversal of 21321415 is 51412312.

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 21321415 - 2³ = 21321407 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21321392 and 21321401.

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 7 ways as a sum of consecutive naturals, for example, 4410 + ... + 7879.

It is an arithmetic number, because the mean of its divisors is an integer number (3207690).

Almost surely, 2^21321415 is an apocalyptic number.

21321415 is a deficient number, since it is larger than the sum of its proper divisors (4340105).

21321415 is a wasteful number, since it uses less digits than its factorization.

21321415 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12641.

The product of its digits is 240, while the sum is 19.

The square root of 21321415 is about 4617.5117758377. The cubic root of 21321415 is about 277.2928519267.

Adding to 21321415 its reverse (51412312), we get a palindrome (72733727).

It can be divided in two parts, 21321 and 415, that added together give a triangular number (21736 = T₂₀₈).

The spelling of 21321415 in words is "twenty-one million, three hundred twenty-one thousand, four hundred fifteen".