1661223040 has 192 divisors, whose sum is σ = 4272243480. Its totient is φ = 617103360.

The previous prime is 1661223023. The next prime is 1661223049. The reversal of 1661223040 is 403221661.

It can be written as a sum of positive squares in 4 ways, for example, as 1594245184 + 66977856 = 39928^2 + 8184^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1661222996 and 1661223014.

It is not an unprimeable number, because it can be changed into a prime (1661223049) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22756444 + ... + 22756516.

Almost surely, 2^1661223040 is an apocalyptic number.

1661223040 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 1661223040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2136121740).

1661223040 is an abundant number, since it is smaller than the sum of its proper divisors (2611020440).

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

1661223040 is an equidigital number, since it uses as much as digits as its factorization.

1661223040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 1661223040 is about 40758.1039794542. The cubic root of 1661223040 is about 1184.3388669692.

The spelling of 1661223040 in words is "one billion, six hundred sixty-one million, two hundred twenty-three thousand, forty".