128561688025 has 9 divisors (see below), whose sum is σ = 159418716223. Its totient is φ = 102847916200.

The previous prime is 128561687983. The next prime is 128561688049. The reversal of 128561688025 is 520886165821.

The square root of 128561688025 is 358555.

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., 46282207689 + 82279480336 = 215133^2 + 286844^2 .

It is not a de Polignac number, because 128561688025 - 2¹³ = 128561679833 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, 1756920 + ... + 1828630.

Almost surely, 2^128561688025 is an apocalyptic number.

128561688025 is the 358555-th square number.

128561688025 is the 179278-th centered octagonal number.

It is an amenable number.

128561688025 is a deficient number, since it is larger than the sum of its proper divisors (30857028198).

128561688025 is an frugal number, since it uses more digits than its factorization.

128561688025 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143432 (or 71716 counting only the distinct ones).

The product of its (nonzero) digits is 1843200, while the sum is 52.

The spelling of 128561688025 in words is "one hundred twenty-eight billion, five hundred sixty-one million, six hundred eighty-eight thousand, twenty-five".