1261102818661 has 16 divisors (see below), whose sum is σ = 1476037877248. Its totient is φ = 1054905087600.

The previous prime is 1261102818649. The next prime is 1261102818667. The reversal of 1261102818661 is 1668182011621.

It is not a de Polignac number, because 1261102818661 - 2⁷ = 1261102818533 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261102818667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1436475 + ... + 2141416.

It is an arithmetic number, because the mean of its divisors is an integer number (92252367328).

Almost surely, 2^{1261102818661} is an apocalyptic number.

It is an amenable number.

1261102818661 is a deficient number, since it is larger than the sum of its proper divisors (214935058587).

1261102818661 is a wasteful number, since it uses less digits than its factorization.

1261102818661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3579112.

The product of its (nonzero) digits is 55296, while the sum is 43.

The spelling of 1261102818661 in words is "one trillion, two hundred sixty-one billion, one hundred two million, eight hundred eighteen thousand, six hundred sixty-one".