21595601 has 2 divisors, whose sum is σ = 21595602. Its totient is φ = 21595600.

The previous prime is 21595591. The next prime is 21595603. The reversal of 21595601 is 10659512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15840400 + 5755201 = 3980^2 + 2399^2 .

It is a cyclic number.

It is not a de Polignac number, because 21595601 - 2⁶ = 21595537 is a prime.

Together with 21595603, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21595603) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10797800 + 10797801.

It is an arithmetic number, because the mean of its divisors is an integer number (10797801).

Almost surely, 2^21595601 is an apocalyptic number.

It is an amenable number.

21595601 is a deficient number, since it is larger than the sum of its proper divisors (1).

21595601 is an equidigital number, since it uses as much as digits as its factorization.

21595601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2700, while the sum is 29.

The square root of 21595601 is about 4647.1067343025. The cubic root of 21595601 is about 278.4764228542.

The spelling of 21595601 in words is "twenty-one million, five hundred ninety-five thousand, six hundred one".