128949821 has 48 divisors (see below), whose sum is σ = 178752000. Its totient is φ = 92363040.

The previous prime is 128949817. The next prime is 128949829.

128949821 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 128949821 - 2² = 128949817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128949829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 539420 + ... + 539658.

It is an arithmetic number, because the mean of its divisors is an integer number (3724000).

Almost surely, 2^128949821 is an apocalyptic number.

128949821 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

128949821 is a deficient number, since it is larger than the sum of its proper divisors (49802179).

128949821 is a wasteful number, since it uses less digits than its factorization.

128949821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 295 (or 270 counting only the distinct ones).

The product of its digits is 82944, while the sum is 44.

The square root of 128949821 is about 11355.6074694399. The cubic root of 128949821 is about 505.2119111948.

It can be divided in two parts, 128 and 949821, that added together give a palindrome (949949).

The spelling of 128949821 in words is "one hundred twenty-eight million, nine hundred forty-nine thousand, eight hundred twenty-one".