21525017 has 2 divisors, whose sum is σ = 21525018. Its totient is φ = 21525016.

The previous prime is 21525001. The next prime is 21525059. The reversal of 21525017 is 71052512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21381376 + 143641 = 4624^2 + 379^2 .

It is a cyclic number.

It is not a de Polignac number, because 21525017 - 2⁴ = 21525001 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21524983 and 21525001.

It is not a weakly prime, because it can be changed into another prime (21515017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10762508 + 10762509.

It is an arithmetic number, because the mean of its divisors is an integer number (10762509).

Almost surely, 2^21525017 is an apocalyptic number.

It is an amenable number.

21525017 is a deficient number, since it is larger than the sum of its proper divisors (1).

21525017 is an equidigital number, since it uses as much as digits as its factorization.

21525017 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 21525017 is about 4639.5061159567. The cubic root of 21525017 is about 278.1726968991.

Adding to 21525017 its reverse (71052512), we get a palindrome (92577529).

The spelling of 21525017 in words is "twenty-one million, five hundred twenty-five thousand, seventeen".