128956551 has 8 divisors (see below), whose sum is σ = 172485744. Its totient is φ = 85699200.

The previous prime is 128956549. The next prime is 128956571. The reversal of 128956551 is 155659821.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 128956551 - 2¹ = 128956549 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128956511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 66850 + ... + 68751.

It is an arithmetic number, because the mean of its divisors is an integer number (21560718).

Almost surely, 2^128956551 is an apocalyptic number.

128956551 is a deficient number, since it is larger than the sum of its proper divisors (43529193).

128956551 is a wasteful number, since it uses less digits than its factorization.

128956551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135921.

The product of its digits is 108000, while the sum is 42.

The square root of 128956551 is about 11355.9037949430. The cubic root of 128956551 is about 505.2207001873.

The spelling of 128956551 in words is "one hundred twenty-eight million, nine hundred fifty-six thousand, five hundred fifty-one".