11820661938 has 80 divisors (see below), whose sum is σ = 27914641920. Its totient is φ = 3728350944.

The previous prime is 11820661877. The next prime is 11820661967. The reversal of 11820661938 is 83916602811.

11820661938 is a `hidden beast` number, since 1 + 1 + 8 + 20 + 6 + 619 + 3 + 8 = 666.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 11820661893 and 11820661902.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 3344020 + ... + 3347552.

It is an arithmetic number, because the mean of its divisors is an integer number (348933024).

Almost surely, 2^11820661938 is an apocalyptic number.

11820661938 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 11820661938, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13957320960).

11820661938 is an abundant number, since it is smaller than the sum of its proper divisors (16093979982).

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

11820661938 is a wasteful number, since it uses less digits than its factorization.

11820661938 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4653 (or 4644 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 45.

The spelling of 11820661938 in words is "eleven billion, eight hundred twenty million, six hundred sixty-one thousand, nine hundred thirty-eight".