1661186340 has 384 divisors, whose sum is σ = 6096384000. Its totient is φ = 371174400.

The previous prime is 1661186327. The next prime is 1661186341. The reversal of 1661186340 is 436811661.

1661186340 is a `hidden beast` number, since 1 + 6 + 6 + 1 + 18 + 634 + 0 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 1661186295 and 1661186304.

It is not an unprimeable number, because it can be changed into a prime (1661186341) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4627081 + ... + 4627439.

It is an arithmetic number, because the mean of its divisors is an integer number (15876000).

Almost surely, 2^1661186340 is an apocalyptic number.

1661186340 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 1661186340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3048192000).

1661186340 is an abundant number, since it is smaller than the sum of its proper divisors (4435197660).

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

1661186340 is a wasteful number, since it uses less digits than its factorization.

1661186340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 448 (or 440 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 1661186340 is about 40757.6537597541. The cubic root of 1661186340 is about 1184.3301453716.

The spelling of 1661186340 in words is "one billion, six hundred sixty-one million, one hundred eighty-six thousand, three hundred forty".