21241187641 has 2 divisors, whose sum is σ = 21241187642. Its totient is φ = 21241187640.

The previous prime is 21241187623. The next prime is 21241187699. The reversal of 21241187641 is 14678114212.

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., 14302964025 + 6938223616 = 119595^2 + 83296^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21241187641 is a prime.

It is a super-2 number, since 2×21241187641² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21241187641.

It is not a weakly prime, because it can be changed into another prime (21241187741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10620593820 + 10620593821.

It is an arithmetic number, because the mean of its divisors is an integer number (10620593821).

Almost surely, 2^21241187641 is an apocalyptic number.

It is an amenable number.

21241187641 is a deficient number, since it is larger than the sum of its proper divisors (1).

21241187641 is an equidigital number, since it uses as much as digits as its factorization.

21241187641 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21504, while the sum is 37.

The spelling of 21241187641 in words is "twenty-one billion, two hundred forty-one million, one hundred eighty-seven thousand, six hundred forty-one".