1221101685913 has 2 divisors, whose sum is σ = 1221101685914. Its totient is φ = 1221101685912.

The previous prime is 1221101685911. The next prime is 1221101685931. The reversal of 1221101685913 is 3195861011221.

Together with next prime (1221101685931) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1127359779984 + 93741905929 = 1061772^2 + 306173^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221101685913 - 2¹ = 1221101685911 is a prime.

Together with 1221101685911, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1221101685911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610550842956 + 610550842957.

It is an arithmetic number, because the mean of its divisors is an integer number (610550842957).

Almost surely, 2^{1221101685913} is an apocalyptic number.

It is an amenable number.

1221101685913 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221101685913 is an equidigital number, since it uses as much as digits as its factorization.

1221101685913 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 40.

The spelling of 1221101685913 in words is "one trillion, two hundred twenty-one billion, one hundred one million, six hundred eighty-five thousand, nine hundred thirteen".