128216556 has 36 divisors (see below), whose sum is σ = 349035232. Its totient is φ = 39451104.

The previous prime is 128216531. The next prime is 128216603. The reversal of 128216556 is 655612821.

128216556 is a `hidden beast` number, since 12 + 82 + 16 + 556 = 666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×128216556² = 32878970465002272, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 128216556.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 136516 + ... + 137451.

Almost surely, 2^128216556 is an apocalyptic number.

It is an amenable number.

128216556 is an abundant number, since it is smaller than the sum of its proper divisors (220818676).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

128216556 is a wasteful number, since it uses less digits than its factorization.

128216556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 273990 (or 273985 counting only the distinct ones).

The product of its digits is 28800, while the sum is 36.

The square root of 128216556 is about 11323.2749679587. The cubic root of 128216556 is about 504.2524717682.

The spelling of 128216556 in words is "one hundred twenty-eight million, two hundred sixteen thousand, five hundred fifty-six".