11555661601 has 4 divisors (see below), whose sum is σ = 12606176304. Its totient is φ = 10505146900.

The previous prime is 11555661569. The next prime is 11555661629. The reversal of 11555661601 is 10616655511.

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 cyclic number.

It is not a de Polignac number, because 11555661601 - 2⁵ = 11555661569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11555661641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 525257335 + ... + 525257356.

It is an arithmetic number, because the mean of its divisors is an integer number (3151544076).

Almost surely, 2^11555661601 is an apocalyptic number.

11555661601 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11555661601 is a deficient number, since it is larger than the sum of its proper divisors (1050514703).

11555661601 is a wasteful number, since it uses less digits than its factorization.

11555661601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1050514702.

The product of its (nonzero) digits is 27000, while the sum is 37.

The spelling of 11555661601 in words is "eleven billion, five hundred fifty-five million, six hundred sixty-one thousand, six hundred one".