21600641 has 2 divisors, whose sum is σ = 21600642. Its totient is φ = 21600640.

The previous prime is 21600629. The next prime is 21600643. The reversal of 21600641 is 14600612.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13535041 + 8065600 = 3679^2 + 2840^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21600641 is a prime.

It is a super-2 number, since 2×21600641² = 933175383221762, which contains 22 as substring.

Together with 21600643, 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 (21600643) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10800320 + 10800321.

It is an arithmetic number, because the mean of its divisors is an integer number (10800321).

Almost surely, 2^21600641 is an apocalyptic number.

It is an amenable number.

21600641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21600641 is an equidigital number, since it uses as much as digits as its factorization.

21600641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21600641 is about 4647.6489755574. The cubic root of 21600641 is about 278.4980848584.

The spelling of 21600641 in words is "twenty-one million, six hundred thousand, six hundred forty-one".