21307417 has 4 divisors (see below), whose sum is σ = 22428880. Its totient is φ = 20185956.

The previous prime is 21307411. The next prime is 21307421. The reversal of 21307417 is 71470312.

It is a happy number.

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 a de Polignac number, because none of the positive numbers 2^k-21307417 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21307391 and 21307400.

It is not an unprimeable number, because it can be changed into a prime (21307411) 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, 560703 + ... + 560740.

It is an arithmetic number, because the mean of its divisors is an integer number (5607220).

Almost surely, 2^21307417 is an apocalyptic number.

It is an amenable number.

21307417 is a deficient number, since it is larger than the sum of its proper divisors (1121463).

21307417 is a wasteful number, since it uses less digits than its factorization.

21307417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1121462.

The product of its (nonzero) digits is 1176, while the sum is 25.

The square root of 21307417 is about 4615.9957755613. The cubic root of 21307417 is about 277.2321555941.

Adding to 21307417 its reverse (71470312), we get a palindrome (92777729).

The spelling of 21307417 in words is "twenty-one million, three hundred seven thousand, four hundred seventeen".