1566808989881 has 2 divisors, whose sum is σ = 1566808989882. Its totient is φ = 1566808989880.

The previous prime is 1566808989857. The next prime is 1566808989923. The reversal of 1566808989881 is 1889898086651.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1218639366400 + 348169623481 = 1103920^2 + 590059^2 .

It is a cyclic number.

It is not a de Polignac number, because 1566808989881 - 2¹⁴ = 1566808973497 is a prime.

It is a super-2 number, since 2×1566808989881² (a number of 25 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1566808989281) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 783404494940 + 783404494941.

It is an arithmetic number, because the mean of its divisors is an integer number (783404494941).

Almost surely, 2^{1566808989881} is an apocalyptic number.

It is an amenable number.

1566808989881 is a deficient number, since it is larger than the sum of its proper divisors (1).

1566808989881 is an equidigital number, since it uses as much as digits as its factorization.

1566808989881 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 477757440, while the sum is 77.

The spelling of 1566808989881 in words is "one trillion, five hundred sixty-six billion, eight hundred eight million, nine hundred eighty-nine thousand, eight hundred eighty-one".