1661194440 has 256 divisors, whose sum is σ = 5908204800. Its totient is φ = 413724672.

The previous prime is 1661194411. The next prime is 1661194463. The reversal of 1661194440 is 444911661.

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 = 1661194395 and 1661194404.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3176019 + ... + 3176541.

It is an arithmetic number, because the mean of its divisors is an integer number (23078925).

Almost surely, 2^1661194440 is an apocalyptic number.

1661194440 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 1661194440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2954102400).

1661194440 is an abundant number, since it is smaller than the sum of its proper divisors (4247010360).

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

1661194440 is a wasteful number, since it uses less digits than its factorization.

1661194440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 733 (or 723 counting only the distinct ones).

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

The square root of 1661194440 is about 40757.7531274726. The cubic root of 1661194440 is about 1184.3320703129.

The spelling of 1661194440 in words is "one billion, six hundred sixty-one million, one hundred ninety-four thousand, four hundred forty".