21430505 has 8 divisors (see below), whose sum is σ = 25790400. Its totient is φ = 17095216.

The previous prime is 21430481. The next prime is 21430529. The reversal of 21430505 is 50503412.

It is an interprime number because it is at equal distance from previous prime (21430481) and next prime (21430529).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21430505 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4175 + ... + 7764.

It is an arithmetic number, because the mean of its divisors is an integer number (3223800).

Almost surely, 2^21430505 is an apocalyptic number.

It is an amenable number.

21430505 is a deficient number, since it is larger than the sum of its proper divisors (4359895).

21430505 is a wasteful number, since it uses less digits than its factorization.

21430505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12303.

The product of its (nonzero) digits is 600, while the sum is 20.

The square root of 21430505 is about 4629.3093437358. The cubic root of 21430505 is about 277.7649661943.

Adding to 21430505 its reverse (50503412), we get a palindrome (71933917).

The spelling of 21430505 in words is "twenty-one million, four hundred thirty thousand, five hundred five".