21321417 has 16 divisors (see below), whose sum is σ = 32417280. Its totient is φ = 12348672.

The previous prime is 21321407. The next prime is 21321431. The reversal of 21321417 is 71412312.

It is not a de Polignac number, because 21321417 - 2¹⁸ = 21059273 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21321393 and 21321402.

It is not an unprimeable number, because it can be changed into a prime (21321407) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15417 + ... + 16742.

It is an arithmetic number, because the mean of its divisors is an integer number (2026080).

Almost surely, 2^21321417 is an apocalyptic number.

It is an amenable number.

21321417 is a deficient number, since it is larger than the sum of its proper divisors (11095863).

21321417 is a wasteful number, since it uses less digits than its factorization.

21321417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32192.

The product of its digits is 336, while the sum is 21.

The square root of 21321417 is about 4617.5119924046. The cubic root of 21321417 is about 277.2928605970.

Adding to 21321417 its reverse (71412312), we get a palindrome (92733729).

The spelling of 21321417 in words is "twenty-one million, three hundred twenty-one thousand, four hundred seventeen".