1681936641025 has 9 divisors (see below), whose sum is σ = 2085609475651. Its totient is φ = 1345544125240.

The previous prime is 1681936640999. The next prime is 1681936641029. The reversal of 1681936641025 is 5201466391861.

It is a happy number.

The square root of 1681936641025 is 1296895.

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

It can be written as a sum of positive squares in only one way, i.e., 605497190769 + 1076439450256 = 778137^2 + 1037516^2 .

It is not a de Polignac number, because 1681936641025 - 2⁹ = 1681936640513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1681936641029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 6354786 + ... + 6614164.

Almost surely, 2^{1681936641025} is an apocalyptic number.

1681936641025 is the 1296895-th square number.

1681936641025 is the 648448-th centered octagonal number.

It is an amenable number.

1681936641025 is a deficient number, since it is larger than the sum of its proper divisors (403672834626).

1681936641025 is an frugal number, since it uses more digits than its factorization.

1681936641025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 518768 (or 259384 counting only the distinct ones).

The product of its (nonzero) digits is 1866240, while the sum is 52.

The spelling of 1681936641025 in words is "one trillion, six hundred eighty-one billion, nine hundred thirty-six million, six hundred forty-one thousand, twenty-five".