11661501666501 has 24 divisors (see below), whose sum is σ = 17580429397440. Its totient is φ = 7434765830976.

The previous prime is 11661501666431. The next prime is 11661501666569. The reversal of 11661501666501 is 10566610516611.

It is not a de Polignac number, because 11661501666501 - 2¹⁰ = 11661501665477 is a prime.

It is a super-2 number, since 2×11661501666501² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11661501666601) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4893336 + ... + 6875153.

It is an arithmetic number, because the mean of its divisors is an integer number (732517891560).

Almost surely, 2^{11661501666501} is an apocalyptic number.

It is an amenable number.

11661501666501 is a deficient number, since it is larger than the sum of its proper divisors (5918927730939).

11661501666501 is a wasteful number, since it uses less digits than its factorization.

11661501666501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11773305 (or 11773302 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 45.

The spelling of 11661501666501 in words is "eleven trillion, six hundred sixty-one billion, five hundred one million, six hundred sixty-six thousand, five hundred one".