1011220211681 has 2 divisors, whose sum is σ = 1011220211682. Its totient is φ = 1011220211680.

The previous prime is 1011220211627. The next prime is 1011220211689. The reversal of 1011220211681 is 1861120221101.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 771331845025 + 239888366656 = 878255^2 + 489784^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1011220211681 is a prime.

It is a super-2 number, since 2×1011220211681² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1011220211681.

It is not a weakly prime, because it can be changed into another prime (1011220211689) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 505610105840 + 505610105841.

It is an arithmetic number, because the mean of its divisors is an integer number (505610105841).

Almost surely, 2^{1011220211681} is an apocalyptic number.

It is an amenable number.

1011220211681 is a deficient number, since it is larger than the sum of its proper divisors (1).

1011220211681 is an equidigital number, since it uses as much as digits as its factorization.

1011220211681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 384, while the sum is 26.

Adding to 1011220211681 its reverse (1861120221101), we get a palindrome (2872340432782).

The spelling of 1011220211681 in words is "one trillion, eleven billion, two hundred twenty million, two hundred eleven thousand, six hundred eighty-one".