128632861 has 4 divisors (see below), whose sum is σ = 147008992. Its totient is φ = 110256732.

The previous prime is 128632811. The next prime is 128632873. The reversal of 128632861 is 168236821.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 128632861 - 2²⁵ = 95078429 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 128632861.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128632811) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9188055 + ... + 9188068.

It is an arithmetic number, because the mean of its divisors is an integer number (36752248).

Almost surely, 2^128632861 is an apocalyptic number.

It is an amenable number.

128632861 is a deficient number, since it is larger than the sum of its proper divisors (18376131).

128632861 is an equidigital number, since it uses as much as digits as its factorization.

128632861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18376130.

The product of its digits is 27648, while the sum is 37.

The square root of 128632861 is about 11341.6427822428. The cubic root of 128632861 is about 504.7976328665.

The spelling of 128632861 in words is "one hundred twenty-eight million, six hundred thirty-two thousand, eight hundred sixty-one".