11661511680 has 1056 divisors, whose sum is σ = 52074107904. Its totient is φ = 2436562944.

The previous prime is 11661511619. The next prime is 11661511691. The reversal of 11661511680 is 8611516611.

11661511680 is a `hidden beast` number, since 1 + 1 + 6 + 61 + 511 + 6 + 80 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 113218509 + ... + 113218611.

Almost surely, 2^11661511680 is an apocalyptic number.

11661511680 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 11661511680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26037053952).

11661511680 is an abundant number, since it is smaller than the sum of its proper divisors (40412596224).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

11661511680 is a wasteful number, since it uses less digits than its factorization.

11661511680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163 (or 133 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 36.

The spelling of 11661511680 in words is "eleven billion, six hundred sixty-one million, five hundred eleven thousand, six hundred eighty".