1935128605921 has 81 divisors (see below), whose sum is σ = 2389596491961. Its totient is φ = 1562471164800.

The previous prime is 1935128605913. The next prime is 1935128605957. The reversal of 1935128605921 is 1295068215391.

The square root of 1935128605921 is 1391089.

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

It can be written as a sum of positive squares in 4 ways, for example, as 22893203025 + 1912235402896 = 151305^2 + 1382836^2 .

It is not a de Polignac number, because 1935128605921 - 2³ = 1935128605913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1935128605321) by changing a digit.

It is a polite number, since it can be written in 80 ways as a sum of consecutive naturals, for example, 14771974026 + ... + 14771974156.

Almost surely, 2^{1935128605921} is an apocalyptic number.

1935128605921 is the 1391089-th square number.

1935128605921 is the 695545-th centered octagonal number.

It is an amenable number.

1935128605921 is a deficient number, since it is larger than the sum of its proper divisors (454467886040).

1935128605921 is an frugal number, since it uses more digits than its factorization.

1935128605921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 432 (or 216 counting only the distinct ones).

The product of its (nonzero) digits is 1166400, while the sum is 52.

The spelling of 1935128605921 in words is "one trillion, nine hundred thirty-five billion, one hundred twenty-eight million, six hundred five thousand, nine hundred twenty-one".