128209540 has 48 divisors (see below), whose sum is σ = 274083264. Its totient is φ = 50371200.

The previous prime is 128209513. The next prime is 128209553. The reversal of 128209540 is 45902821.

It is a super-2 number, since 2×128209540² = 32875372294023200, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 387175 + ... + 387505.

It is an arithmetic number, because the mean of its divisors is an integer number (5710068).

Almost surely, 2^128209540 is an apocalyptic number.

128209540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

128209540 is an abundant number, since it is smaller than the sum of its proper divisors (145873724).

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

128209540 is a wasteful number, since it uses less digits than its factorization.

128209540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 628 (or 626 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 31.

The square root of 128209540 is about 11322.9651593564. The cubic root of 128209540 is about 504.2432740484.

The spelling of 128209540 in words is "one hundred twenty-eight million, two hundred nine thousand, five hundred forty".