128658680813961 has 21 divisors (see below), whose sum is σ = 192900237129309. Its totient is φ = 85772249705916.

The previous prime is 128658680813921. The next prime is 128658680813987. The reversal of 128658680813961 is 169318086856821.

The square root of 128658680813961 is 11342781.

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

128658680813961 is a `hidden beast` number, since 1 + 2 + 8 + 6 + 5 + 86 + 80 + 81 + 396 + 1 = 666.

It is not a de Polignac number, because 128658680813961 - 2³⁹ = 128108925000073 is a prime.

It is a super-2 number, since 2×128658680813961² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 128658680813961.

It is not an unprimeable number, because it can be changed into a prime (128658680813921) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 306045036 + ... + 306465138.

Almost surely, 2^{128658680813961} is an apocalyptic number.

128658680813961 is the 11342781-st square number.

128658680813961 is the 5671391-st centered octagonal number.

It is an amenable number.

128658680813961 is a deficient number, since it is larger than the sum of its proper divisors (64241556315348).

128658680813961 is an frugal number, since it uses more digits than its factorization.

128658680813961 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 840224 (or 420106 counting only the distinct ones).

The product of its (nonzero) digits is 238878720, while the sum is 72.

The spelling of 128658680813961 in words is "one hundred twenty-eight trillion, six hundred fifty-eight billion, six hundred eighty million, eight hundred thirteen thousand, nine hundred sixty-one".