1208409551681 has 16 divisors (see below), whose sum is σ = 1257482307840. Its totient is φ = 1160217302400.

The previous prime is 1208409551669. The next prime is 1208409551689. The reversal of 1208409551681 is 1861559048021.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1208409551681 is a prime.

It is a super-2 number, since 2×1208409551681² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1208409551689) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5149550 + ... + 5379096.

It is an arithmetic number, because the mean of its divisors is an integer number (78592644240).

Almost surely, 2^{1208409551681} is an apocalyptic number.

It is an amenable number.

1208409551681 is a deficient number, since it is larger than the sum of its proper divisors (49072756159).

1208409551681 is a wasteful number, since it uses less digits than its factorization.

1208409551681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231464.

The product of its (nonzero) digits is 691200, while the sum is 50.

The spelling of 1208409551681 in words is "one trillion, two hundred eight billion, four hundred nine million, five hundred fifty-one thousand, six hundred eighty-one".