1220021312161 has 2 divisors, whose sum is σ = 1220021312162. Its totient is φ = 1220021312160.

The previous prime is 1220021312123. The next prime is 1220021312179. The reversal of 1220021312161 is 1612131200221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 938544376225 + 281476935936 = 968785^2 + 530544^2 .

It is an emirp because it is prime and its reverse (1612131200221) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1220021312161 is a prime.

It is not a weakly prime, because it can be changed into another prime (1220021312101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610010656080 + 610010656081.

It is an arithmetic number, because the mean of its divisors is an integer number (610010656081).

Almost surely, 2^{1220021312161} is an apocalyptic number.

It is an amenable number.

1220021312161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220021312161 is an equidigital number, since it uses as much as digits as its factorization.

1220021312161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

Adding to 1220021312161 its reverse (1612131200221), we get a palindrome (2832152512382).

The spelling of 1220021312161 in words is "one trillion, two hundred twenty billion, twenty-one million, three hundred twelve thousand, one hundred sixty-one".