1721643725 has 54 divisors (see below), whose sum is σ = 2343619530. Its totient is φ = 1253017920.

The previous prime is 1721643709. The next prime is 1721643731. The reversal of 1721643725 is 5273461271.

It can be written as a sum of positive squares in 3 ways, for example, as 116359369 + 1605284356 = 10787^2 + 40066^2 .

It is not a de Polignac number, because 1721643725 - 2⁴ = 1721643709 is a prime.

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 53 ways as a sum of consecutive naturals, for example, 25696142 + ... + 25696208.

Almost surely, 2^1721643725 is an apocalyptic number.

It is an amenable number.

1721643725 is a deficient number, since it is larger than the sum of its proper divisors (621975805).

1721643725 is an equidigital number, since it uses as much as digits as its factorization.

1721643725 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 219 (or 124 counting only the distinct ones).

The product of its digits is 70560, while the sum is 38.

The square root of 1721643725 is about 41492.6948389714. The cubic root of 1721643725 is about 1198.5268322671.

The spelling of 1721643725 in words is "one billion, seven hundred twenty-one million, six hundred forty-three thousand, seven hundred twenty-five".