1728643540 has 48 divisors (see below), whose sum is σ = 3932626320. Its totient is φ = 638252160.

The previous prime is 1728643519. The next prime is 1728643547. The reversal of 1728643540 is 453468271.

It can be written as a sum of positive squares in 8 ways, for example, as 1637173444 + 91470096 = 40462^2 + 9564^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1728643493 and 1728643502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1728643547) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24270 + ... + 63610.

It is an arithmetic number, because the mean of its divisors is an integer number (81929715).

Almost surely, 2^1728643540 is an apocalyptic number.

1728643540 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 1728643540, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1966313160).

1728643540 is an abundant number, since it is smaller than the sum of its proper divisors (2203982780).

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

1728643540 is a wasteful number, since it uses less digits than its factorization.

1728643540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39389 (or 39361 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 40.

The square root of 1728643540 is about 41576.9592442737. The cubic root of 1728643540 is about 1200.1489491036.

The spelling of 1728643540 in words is "one billion, seven hundred twenty-eight million, six hundred forty-three thousand, five hundred forty".