21120221185837 has 2 divisors, whose sum is σ = 21120221185838. Its totient is φ = 21120221185836.

The previous prime is 21120221185787. The next prime is 21120221185841. The reversal of 21120221185837 is 73858112202112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19862299677796 + 1257921508041 = 4456714^2 + 1121571^2 .

It is a cyclic number.

It is not a de Polignac number, because 21120221185837 - 2¹⁹ = 21120220661549 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21120221185793 and 21120221185802.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21120221186837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560110592918 + 10560110592919.

It is an arithmetic number, because the mean of its divisors is an integer number (10560110592919).

Almost surely, 2^{21120221185837} is an apocalyptic number.

It is an amenable number.

21120221185837 is a deficient number, since it is larger than the sum of its proper divisors (1).

21120221185837 is an equidigital number, since it uses as much as digits as its factorization.

21120221185837 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 107520, while the sum is 43.

Adding to 21120221185837 its reverse (73858112202112), we get a palindrome (94978333387949).

The spelling of 21120221185837 in words is "twenty-one trillion, one hundred twenty billion, two hundred twenty-one million, one hundred eighty-five thousand, eight hundred thirty-seven".