128491387 has 8 divisors (see below), whose sum is σ = 130248720. Its totient is φ = 126739200.

The previous prime is 128491381. The next prime is 128491397. The reversal of 128491387 is 783194821.

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 128491387 - 2³ = 128491379 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128491381) 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, 99039 + ... + 100327.

It is an arithmetic number, because the mean of its divisors is an integer number (16281090).

Almost surely, 2^128491387 is an apocalyptic number.

128491387 is a deficient number, since it is larger than the sum of its proper divisors (1757333).

128491387 is a wasteful number, since it uses less digits than its factorization.

128491387 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2573.

The product of its digits is 96768, while the sum is 43.

The square root of 128491387 is about 11335.4041392444. The cubic root of 128491387 is about 504.6125014844.

The spelling of 128491387 in words is "one hundred twenty-eight million, four hundred ninety-one thousand, three hundred eighty-seven".