221710400861 has 2 divisors, whose sum is σ = 221710400862. Its totient is φ = 221710400860.

The previous prime is 221710400767. The next prime is 221710400893. The reversal of 221710400861 is 168004017122.

It is a happy number.

It is an a-pointer prime, because the next prime (221710400893) can be obtained adding 221710400861 to its sum of digits (32).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 113818516900 + 107891883961 = 337370^2 + 328469^2 .

It is a cyclic number.

It is not a de Polignac number, because 221710400861 - 2¹⁰ = 221710399837 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 (221710400161) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110855200430 + 110855200431.

It is an arithmetic number, because the mean of its divisors is an integer number (110855200431).

Almost surely, 2^221710400861 is an apocalyptic number.

It is an amenable number.

221710400861 is a deficient number, since it is larger than the sum of its proper divisors (1).

221710400861 is an equidigital number, since it uses as much as digits as its factorization.

221710400861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5376, while the sum is 32.

Adding to 221710400861 its reverse (168004017122), we get a palindrome (389714417983).

The spelling of 221710400861 in words is "two hundred twenty-one billion, seven hundred ten million, four hundred thousand, eight hundred sixty-one".