21425017 has 4 divisors (see below), whose sum is σ = 21434356. Its totient is φ = 21415680.

The previous prime is 21425009. The next prime is 21425021. The reversal of 21425017 is 71052412.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 6533136 + 14891881 = 2556^2 + 3859^2 .

It is a cyclic number.

It is not a de Polignac number, because 21425017 - 2³ = 21425009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21425057) 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, 1417 + ... + 6697.

It is an arithmetic number, because the mean of its divisors is an integer number (5358589).

Almost surely, 2^21425017 is an apocalyptic number.

It is an amenable number.

21425017 is a deficient number, since it is larger than the sum of its proper divisors (9339).

21425017 is an equidigital number, since it uses as much as digits as its factorization.

21425017 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9338.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 21425017 is about 4628.7165607758. The cubic root of 21425017 is about 277.7412538230.

Adding to 21425017 its reverse (71052412), we get a palindrome (92477429).

The spelling of 21425017 in words is "twenty-one million, four hundred twenty-five thousand, seventeen".