1721665340 has 48 divisors (see below), whose sum is σ = 3653766144. Its totient is φ = 681408000.

The previous prime is 1721665339. The next prime is 1721665369. The reversal of 1721665340 is 435661271.

It is a self number, because there is not a number n which added to its sum of digits gives 1721665340.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1322690 + ... + 1323990.

It is an arithmetic number, because the mean of its divisors is an integer number (76120128).

Almost surely, 2^1721665340 is an apocalyptic number.

1721665340 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1721665340 is an abundant number, since it is smaller than the sum of its proper divisors (1932100804).

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

1721665340 is a wasteful number, since it uses less digits than its factorization.

1721665340 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1958 (or 1956 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 1721665340 is about 41492.9553056901. The cubic root of 1721665340 is about 1198.5318480259.

The spelling of 1721665340 in words is "one billion, seven hundred twenty-one million, six hundred sixty-five thousand, three hundred forty".