128609551 has 8 divisors (see below), whose sum is σ = 148843520. Its totient is φ = 108840888.

The previous prime is 128609527. The next prime is 128609561. The reversal of 128609551 is 155906821.

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

It is a cyclic number.

It is not a de Polignac number, because 128609551 - 2¹⁷ = 128478479 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 128609551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128609561) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 115731 + ... + 116836.

It is an arithmetic number, because the mean of its divisors is an integer number (18605440).

Almost surely, 2^128609551 is an apocalyptic number.

128609551 is a deficient number, since it is larger than the sum of its proper divisors (20233969).

128609551 is an equidigital number, since it uses as much as digits as its factorization.

128609551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 232653.

The product of its (nonzero) digits is 21600, while the sum is 37.

The square root of 128609551 is about 11340.6151067744. The cubic root of 128609551 is about 504.7671389901.

The spelling of 128609551 in words is "one hundred twenty-eight million, six hundred nine thousand, five hundred fifty-one".