1181099920 has 400 divisors, whose sum is σ = 3851128512. Its totient is φ = 331914240.

The previous prime is 1181099897. The next prime is 1181099951. The reversal of 1181099920 is 299901811.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 27467419 + ... + 27467461.

Almost surely, 2^1181099920 is an apocalyptic number.

1181099920 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 1181099920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1925564256).

1181099920 is an abundant number, since it is smaller than the sum of its proper divisors (2670028592).

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

1181099920 is a wasteful number, since it uses less digits than its factorization.

1181099920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 108 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 40.

The square root of 1181099920 is about 34367.1343000839. The cubic root of 1181099920 is about 1057.0500392959.

The spelling of 1181099920 in words is "one billion, one hundred eighty-one million, ninety-nine thousand, nine hundred twenty".