128720187 has 12 divisors (see below), whose sum is σ = 188977984. Its totient is φ = 84406320.

The previous prime is 128720177. The next prime is 128720191. The reversal of 128720187 is 781027821.

It is a happy number.

It is not a de Polignac number, because 128720187 - 2²⁶ = 61611323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128720147) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 116683 + ... + 117780.

Almost surely, 2^128720187 is an apocalyptic number.

128720187 is a deficient number, since it is larger than the sum of its proper divisors (60257797).

128720187 is a wasteful number, since it uses less digits than its factorization.

128720187 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 234530 (or 234527 counting only the distinct ones).

The product of its (nonzero) digits is 12544, while the sum is 36.

The square root of 128720187 is about 11345.4919241080. The cubic root of 128720187 is about 504.9118390034.

The spelling of 128720187 in words is "one hundred twenty-eight million, seven hundred twenty thousand, one hundred eighty-seven".