1661646272 has 112 divisors (see below), whose sum is σ = 3957230592. Its totient is φ = 682183680.

The previous prime is 1661646229. The next prime is 1661646277. The reversal of 1661646272 is 2726461661.

It is a happy number.

It is a super-2 number, since 2×1661646272² = 5522136666502995968, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661646277) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 428213 + ... + 432075.

It is an arithmetic number, because the mean of its divisors is an integer number (35332416).

Almost surely, 2^1661646272 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661646272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1978615296).

1661646272 is an abundant number, since it is smaller than the sum of its proper divisors (2295584320).

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

1661646272 is a wasteful number, since it uses less digits than its factorization.

1661646272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3946 (or 3936 counting only the distinct ones).

The product of its digits is 145152, while the sum is 41.

The square root of 1661646272 is about 40763.2956469420. The cubic root of 1661646272 is about 1184.4394369576.

The spelling of 1661646272 in words is "one billion, six hundred sixty-one million, six hundred forty-six thousand, two hundred seventy-two".