111220021261 has 2 divisors, whose sum is σ = 111220021262. Its totient is φ = 111220021260.

The previous prime is 111220021249. The next prime is 111220021271. The reversal of 111220021261 is 162120022111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 111098889225 + 121132036 = 333315^2 + 11006^2 .

It is an emirp because it is prime and its reverse (162120022111) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111220021261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111220021271) 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, 55610010630 + 55610010631.

It is an arithmetic number, because the mean of its divisors is an integer number (55610010631).

Almost surely, 2^111220021261 is an apocalyptic number.

It is an amenable number.

111220021261 is a deficient number, since it is larger than the sum of its proper divisors (1).

111220021261 is an equidigital number, since it uses as much as digits as its factorization.

111220021261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 19.

Adding to 111220021261 its reverse (162120022111), we get a palindrome (273340043372).

The spelling of 111220021261 in words is "one hundred eleven billion, two hundred twenty million, twenty-one thousand, two hundred sixty-one".