11566456381 has 2 divisors, whose sum is σ = 11566456382. Its totient is φ = 11566456380.

The previous prime is 11566456339. The next prime is 11566456417. The reversal of 11566456381 is 18365466511.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11468268100 + 98188281 = 107090^2 + 9909^2 .

It is a cyclic number.

It is not a de Polignac number, because 11566456381 - 2¹⁹ = 11565932093 is a prime.

It is a super-2 number, since 2×11566456381² (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 (11566456981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5783228190 + 5783228191.

It is an arithmetic number, because the mean of its divisors is an integer number (5783228191).

Almost surely, 2^11566456381 is an apocalyptic number.

It is an amenable number.

11566456381 is a deficient number, since it is larger than the sum of its proper divisors (1).

11566456381 is an equidigital number, since it uses as much as digits as its factorization.

11566456381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 518400, while the sum is 46.

The spelling of 11566456381 in words is "eleven billion, five hundred sixty-six million, four hundred fifty-six thousand, three hundred eighty-one".