1211011111931 has 2 divisors, whose sum is σ = 1211011111932. Its totient is φ = 1211011111930.

The previous prime is 1211011111909. The next prime is 1211011111957. The reversal of 1211011111931 is 1391111101121.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1211011111931 - 2³⁰ = 1209937370107 is a prime.

It is a super-2 number, since 2×1211011111931² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1211011111897 and 1211011111906.

It is not a weakly prime, because it can be changed into another prime (1211011111991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 605505555965 + 605505555966.

It is an arithmetic number, because the mean of its divisors is an integer number (605505555966).

Almost surely, 2^{1211011111931} is an apocalyptic number.

1211011111931 is a deficient number, since it is larger than the sum of its proper divisors (1).

1211011111931 is an equidigital number, since it uses as much as digits as its factorization.

1211011111931 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54, while the sum is 23.

The spelling of 1211011111931 in words is "one trillion, two hundred eleven billion, eleven million, one hundred eleven thousand, nine hundred thirty-one".