128556377 has 4 divisors (see below), whose sum is σ = 128587956. Its totient is φ = 128524800.

The previous prime is 128556359. The next prime is 128556383. The reversal of 128556377 is 773655821.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 773655821 = 599 ⋅1291579.

It can be written as a sum of positive squares in 2 ways, for example, as 44302336 + 84254041 = 6656^2 + 9179^2 .

It is a cyclic number.

It is not a de Polignac number, because 128556377 - 2⁸ = 128556121 is a prime.

It is a super-2 number, since 2×128556377² = 33053484134732258, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128556347) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8588 + ... + 18189.

It is an arithmetic number, because the mean of its divisors is an integer number (32146989).

Almost surely, 2^128556377 is an apocalyptic number.

It is an amenable number.

128556377 is a deficient number, since it is larger than the sum of its proper divisors (31579).

128556377 is an equidigital number, since it uses as much as digits as its factorization.

128556377 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31578.

The product of its digits is 352800, while the sum is 44.

The square root of 128556377 is about 11338.2704589368. The cubic root of 128556377 is about 504.6975635774.

The spelling of 128556377 in words is "one hundred twenty-eight million, five hundred fifty-six thousand, three hundred seventy-seven".