1321555111261 has 8 divisors (see below), whose sum is σ = 1647653125824. Its totient is φ = 1029783203520.

The previous prime is 1321555111193. The next prime is 1321555111267. The reversal of 1321555111261 is 1621115551231.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1321555111261 - 2⁹ = 1321555110749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1321555111267) 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 7 ways as a sum of consecutive naturals, for example, 8581526620 + ... + 8581526773.

It is an arithmetic number, because the mean of its divisors is an integer number (205956640728).

Almost surely, 2^{1321555111261} is an apocalyptic number.

1321555111261 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1321555111261 is a deficient number, since it is larger than the sum of its proper divisors (326098014563).

1321555111261 is a wasteful number, since it uses less digits than its factorization.

1321555111261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17163053411.

The product of its digits is 9000, while the sum is 34.

The spelling of 1321555111261 in words is "one trillion, three hundred twenty-one billion, five hundred fifty-five million, one hundred eleven thousand, two hundred sixty-one".