128266066862521 has 9 divisors (see below), whose sum is σ = 149207557755621. Its totient is φ = 109942275072252.

The previous prime is 128266066862513. The next prime is 128266066862561. The reversal of 128266066862521 is 125268660662821.

The square root of 128266066862521 is 11325461.

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

It is not a de Polignac number, because 128266066862521 - 2³ = 128266066862513 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128266066862521.

It is not an unprimeable number, because it can be changed into a prime (128266066862561) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 78469266 + ... + 80087188.

Almost surely, 2^{128266066862521} is an apocalyptic number.

128266066862521 is the 11325461-st square number.

128266066862521 is the 5662731-st centered octagonal number.

It is an amenable number.

128266066862521 is a deficient number, since it is larger than the sum of its proper divisors (20941490893100).

128266066862521 is an frugal number, since it uses more digits than its factorization.

128266066862521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3235860 (or 1617930 counting only the distinct ones).

The product of its (nonzero) digits is 39813120, while the sum is 61.

The spelling of 128266066862521 in words is "one hundred twenty-eight trillion, two hundred sixty-six billion, sixty-six million, eight hundred sixty-two thousand, five hundred twenty-one".