11973821 has 2 divisors, whose sum is σ = 11973822. Its totient is φ = 11973820.

The previous prime is 11973799. The next prime is 11973833. The reversal of 11973821 is 12837911.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 9765625 + 2208196 = 3125^2 + 1486^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11973821 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11973851) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5986910 + 5986911.

It is an arithmetic number, because the mean of its divisors is an integer number (5986911).

Almost surely, 2^11973821 is an apocalyptic number.

It is an amenable number.

11973821 is a deficient number, since it is larger than the sum of its proper divisors (1).

11973821 is an equidigital number, since it uses as much as digits as its factorization.

11973821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3024, while the sum is 32.

The square root of 11973821 is about 3460.3209388726. The cubic root of 11973821 is about 228.7762413285.

The spelling of 11973821 in words is "eleven million, nine hundred seventy-three thousand, eight hundred twenty-one".