21490017 has 4 divisors (see below), whose sum is σ = 28653360. Its totient is φ = 14326676.

The previous prime is 21490013. The next prime is 21490031. The reversal of 21490017 is 71009412.

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 21490017 - 2² = 21490013 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21490013) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 3581667 + ... + 3581672.

It is an arithmetic number, because the mean of its divisors is an integer number (7163340).

Almost surely, 2^21490017 is an apocalyptic number.

It is an amenable number.

21490017 is a deficient number, since it is larger than the sum of its proper divisors (7163343).

21490017 is an equidigital number, since it uses as much as digits as its factorization.

21490017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7163342.

The product of its (nonzero) digits is 504, while the sum is 24.

The square root of 21490017 is about 4635.7326281829. The cubic root of 21490017 is about 278.0218441162.

Adding to 21490017 its reverse (71009412), we get a palindrome (92499429).

The spelling of 21490017 in words is "twenty-one million, four hundred ninety thousand, seventeen".