11950643821 has 2 divisors, whose sum is σ = 11950643822. Its totient is φ = 11950643820.

The previous prime is 11950643737. The next prime is 11950643839. The reversal of 11950643821 is 12834605911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9837862596 + 2112781225 = 99186^2 + 45965^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11950643821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11950643851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5975321910 + 5975321911.

It is an arithmetic number, because the mean of its divisors is an integer number (5975321911).

Almost surely, 2^11950643821 is an apocalyptic number.

It is an amenable number.

11950643821 is a deficient number, since it is larger than the sum of its proper divisors (1).

11950643821 is an equidigital number, since it uses as much as digits as its factorization.

11950643821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 51840, while the sum is 40.

The spelling of 11950643821 in words is "eleven billion, nine hundred fifty million, six hundred forty-three thousand, eight hundred twenty-one".