1553281261681 has 4 divisors (see below), whose sum is σ = 1603387108864. Its totient is φ = 1503175414500.

The previous prime is 1553281261657. The next prime is 1553281261687. The reversal of 1553281261681 is 1861621823551.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a de Polignac number, because none of the positive numbers 2^k-1553281261681 is a prime.

It is a super-2 number, since 2×1553281261681² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1553281261687) 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 3 ways as a sum of consecutive naturals, for example, 25052923545 + ... + 25052923606.

It is an arithmetic number, because the mean of its divisors is an integer number (400846777216).

Almost surely, 2^{1553281261681} is an apocalyptic number.

It is an amenable number.

1553281261681 is a deficient number, since it is larger than the sum of its proper divisors (50105847183).

1553281261681 is an equidigital number, since it uses as much as digits as its factorization.

1553281261681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50105847182.

The product of its digits is 691200, while the sum is 49.

The spelling of 1553281261681 in words is "one trillion, five hundred fifty-three billion, two hundred eighty-one million, two hundred sixty-one thousand, six hundred eighty-one".