11111645981 has 2 divisors, whose sum is σ = 11111645982. Its totient is φ = 11111645980.

The previous prime is 11111645959. The next prime is 11111646011. The reversal of 11111645981 is 18954611111.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7479655225 + 3631990756 = 86485^2 + 60266^2 .

It is a cyclic number.

It is not a de Polignac number, because 11111645981 - 2³⁰ = 10037904157 is a prime.

It is a super-2 number, since 2×11111645981² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11111645081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5555822990 + 5555822991.

It is an arithmetic number, because the mean of its divisors is an integer number (5555822991).

Almost surely, 2^11111645981 is an apocalyptic number.

It is an amenable number.

11111645981 is a deficient number, since it is larger than the sum of its proper divisors (1).

11111645981 is an equidigital number, since it uses as much as digits as its factorization.

11111645981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8640, while the sum is 38.

The spelling of 11111645981 in words is "eleven billion, one hundred eleven million, six hundred forty-five thousand, nine hundred eighty-one".