21120221186837 has 2 divisors, whose sum is σ = 21120221186838. Its totient is φ = 21120221186836.

The previous prime is 21120221186819. The next prime is 21120221186851. The reversal of 21120221186837 is 73868112202112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15756763531441 + 5363457655396 = 3969479^2 + 2315914^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120221186837 - 2⁶ = 21120221186773 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120221186807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560110593418 + 10560110593419.

It is an arithmetic number, because the mean of its divisors is an integer number (10560110593419).

Almost surely, 2^{21120221186837} is an apocalyptic number.

It is an amenable number.

21120221186837 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120221186837 is an equidigital number, since it uses as much as digits as its factorization.

21120221186837 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 129024, while the sum is 44.

Adding to 21120221186837 its reverse (73868112202112), we get a palindrome (94988333388949).

The spelling of 21120221186837 in words is "twenty-one trillion, one hundred twenty billion, two hundred twenty-one million, one hundred eighty-six thousand, eight hundred thirty-seven".