1921647475225 has 9 divisors (see below), whose sum is σ = 2382851463967. Its totient is φ = 1537312435240.

The previous prime is 1921647475207. The next prime is 1921647475261. The reversal of 1921647475225 is 5225747461291.

The square root of 1921647475225 is 1386235.

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., 691793091081 + 1229854384144 = 831741^2 + 1108988^2 .

It is not a de Polignac number, because 1921647475225 - 2²³ = 1921639086617 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 6792552 + ... + 7069798.

Almost surely, 2^{1921647475225} is an apocalyptic number.

1921647475225 is the 1386235-th square number.

1921647475225 is the 693118-th centered octagonal number.

It is an amenable number.

1921647475225 is a deficient number, since it is larger than the sum of its proper divisors (461203988742).

1921647475225 is an frugal number, since it uses more digits than its factorization.

1921647475225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 554504 (or 277252 counting only the distinct ones).

The product of its digits is 8467200, while the sum is 55.

The spelling of 1921647475225 in words is "one trillion, nine hundred twenty-one billion, six hundred forty-seven million, four hundred seventy-five thousand, two hundred twenty-five".