1191916861380 has 288 divisors, whose sum is σ = 4287268387584. Its totient is φ = 272294866944.

The previous prime is 1191916861339. The next prime is 1191916861381. The reversal of 1191916861380 is 831686191911.

It is a happy number.

1191916861380 is a `hidden beast` number, since 1 + 1 + 9 + 1 + 9 + 16 + 8 + 613 + 8 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (1191916861381) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 73236924 + ... + 73253196.

It is an arithmetic number, because the mean of its divisors is an integer number (14886348568).

Almost surely, 2^{1191916861380} is an apocalyptic number.

1191916861380 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 1191916861380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2143634193792).

1191916861380 is an abundant number, since it is smaller than the sum of its proper divisors (3095351526204).

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

1191916861380 is a wasteful number, since it uses less digits than its factorization.

1191916861380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18457 (or 18443 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 54.

The spelling of 1191916861380 in words is "one trillion, one hundred ninety-one billion, nine hundred sixteen million, eight hundred sixty-one thousand, three hundred eighty".