128621550 has 48 divisors (see below), whose sum is σ = 324233712. Its totient is φ = 33734400.

The previous prime is 128621539. The next prime is 128621579. The reversal of 128621550 is 55126821.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2122 + ... + 16178.

It is an arithmetic number, because the mean of its divisors is an integer number (6754869).

Almost surely, 2^128621550 is an apocalyptic number.

128621550 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 128621550, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (162116856).

128621550 is an abundant number, since it is smaller than the sum of its proper divisors (195612162).

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

128621550 is a wasteful number, since it uses less digits than its factorization.

128621550 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14133 (or 14128 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 30.

The square root of 128621550 is about 11341.1441221774. The cubic root of 128621550 is about 504.7828364053.

The spelling of 128621550 in words is "one hundred twenty-eight million, six hundred twenty-one thousand, five hundred fifty".