1647821505625 has 15 divisors (see below), whose sum is σ = 2059157856217. Its totient is φ = 1318231531000.

The previous prime is 1647821505587. The next prime is 1647821505643. The reversal of 1647821505625 is 5265051287461.

The square root of 1647821505625 is 1283675.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 129189206041 + 1518632299584 = 359429^2 + 1232328^2 .

It is not a de Polignac number, because 1647821505625 - 2⁷ = 1647821505497 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 32066202 + ... + 32117548.

Almost surely, 2^{1647821505625} is an apocalyptic number.

1647821505625 is the 1283675-th square number.

1647821505625 is the 641838-th centered octagonal number.

It is an amenable number.

1647821505625 is a deficient number, since it is larger than the sum of its proper divisors (411336350592).

1647821505625 is an frugal number, since it uses more digits than its factorization.

1647821505625 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102714 (or 51352 counting only the distinct ones).

The product of its (nonzero) digits is 4032000, while the sum is 52.

The spelling of 1647821505625 in words is "one trillion, six hundred forty-seven billion, eight hundred twenty-one million, five hundred five thousand, six hundred twenty-five".