128809947 has 16 divisors (see below), whose sum is σ = 196515072. Its totient is φ = 73518240.

The previous prime is 128809927. The next prime is 128809951. The reversal of 128809947 is 749908821.

It is not a de Polignac number, because 128809947 - 2¹⁶ = 128744411 is a prime.

It is a super-2 number, since 2×128809947² = 33184004892285618, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 128809896 and 128809905.

It is not an unprimeable number, because it can be changed into a prime (128809907) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17233 + ... + 23549.

It is an arithmetic number, because the mean of its divisors is an integer number (12282192).

Almost surely, 2^128809947 is an apocalyptic number.

128809947 is a deficient number, since it is larger than the sum of its proper divisors (67705125).

128809947 is an equidigital number, since it uses as much as digits as its factorization.

128809947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7298.

The product of its (nonzero) digits is 290304, while the sum is 48.

The square root of 128809947 is about 11349.4469909331. The cubic root of 128809947 is about 505.0291745391.

The spelling of 128809947 in words is "one hundred twenty-eight million, eight hundred nine thousand, nine hundred forty-seven".