128538990 has 48 divisors (see below), whose sum is σ = 351795600. Its totient is φ = 32472576.

The previous prime is 128538979. The next prime is 128539001. The reversal of 128538990 is 99835821.

It is a happy number.

128538990 is a `hidden beast` number, since 1 + 28 + 538 + 9 + 90 = 666.

It is an interprime number because it is at equal distance from previous prime (128538979) and next prime (128539001).

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 35875 + ... + 39294.

It is an arithmetic number, because the mean of its divisors is an integer number (7329075).

Almost surely, 2^128538990 is an apocalyptic number.

128538990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

128538990 is an abundant number, since it is smaller than the sum of its proper divisors (223256610).

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

128538990 is a wasteful number, since it uses less digits than its factorization.

128538990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75201 (or 75198 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The square root of 128538990 is about 11337.5036934944. The cubic root of 128538990 is about 504.6748094302.

The spelling of 128538990 in words is "one hundred twenty-eight million, five hundred thirty-eight thousand, nine hundred ninety".