1221111099881 has 2 divisors, whose sum is σ = 1221111099882. Its totient is φ = 1221111099880.

The previous prime is 1221111099853. The next prime is 1221111099907. The reversal of 1221111099881 is 1889901111221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1070570979856 + 150540120025 = 1034684^2 + 387995^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221111099881 - 2²⁶ = 1221043991017 is a prime.

It is a super-2 number, since 2×1221111099881² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1221111029881) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610555549940 + 610555549941.

It is an arithmetic number, because the mean of its divisors is an integer number (610555549941).

Almost surely, 2^{1221111099881} is an apocalyptic number.

It is an amenable number.

1221111099881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221111099881 is an equidigital number, since it uses as much as digits as its factorization.

1221111099881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20736, while the sum is 44.

The spelling of 1221111099881 in words is "one trillion, two hundred twenty-one billion, one hundred eleven million, ninety-nine thousand, eight hundred eighty-one".