21418417 has 4 divisors (see below), whose sum is σ = 21874176. Its totient is φ = 20962660.

The previous prime is 21418409. The next prime is 21418433. The reversal of 21418417 is 71481412.

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 21418417 - 2³ = 21418409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21418477) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 227809 + ... + 227902.

It is an arithmetic number, because the mean of its divisors is an integer number (5468544).

Almost surely, 2^21418417 is an apocalyptic number.

It is an amenable number.

21418417 is a deficient number, since it is larger than the sum of its proper divisors (455759).

21418417 is an equidigital number, since it uses as much as digits as its factorization.

21418417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 455758.

The product of its digits is 1792, while the sum is 28.

The square root of 21418417 is about 4628.0035652536. The cubic root of 21418417 is about 277.7127313947.

Adding to 21418417 its reverse (71481412), we get a palindrome (92899829).

The spelling of 21418417 in words is "twenty-one million, four hundred eighteen thousand, four hundred seventeen".