11661211540 has 96 divisors (see below), whose sum is σ = 28567219968. Its totient is φ = 3951360000.

The previous prime is 11661211517. The next prime is 11661211553. The reversal of 11661211540 is 4511216611.

It is a junction number, because it is equal to n+sod(n) for n = 11661211499 and 11661211508.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 362305 + ... + 393175.

It is an arithmetic number, because the mean of its divisors is an integer number (297575208).

Almost surely, 2^11661211540 is an apocalyptic number.

11661211540 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 11661211540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14283609984).

11661211540 is an abundant number, since it is smaller than the sum of its proper divisors (16906008428).

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

11661211540 is a wasteful number, since it uses less digits than its factorization.

11661211540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31009 (or 31007 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 28.

The spelling of 11661211540 in words is "eleven billion, six hundred sixty-one million, two hundred eleven thousand, five hundred forty".