128212749 has 24 divisors (see below), whose sum is σ = 212600960. Its totient is φ = 72936288.

The previous prime is 128212727. The next prime is 128212769. The reversal of 128212749 is 947212821.

It is not a de Polignac number, because 128212749 - 2¹¹ = 128210701 is a prime.

It is a super-2 number, since 2×128212749² = 32877018012274002, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128212709) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9984 + ... + 18870.

Almost surely, 2^128212749 is an apocalyptic number.

It is an amenable number.

128212749 is a deficient number, since it is larger than the sum of its proper divisors (84388211).

128212749 is a wasteful number, since it uses less digits than its factorization.

128212749 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9129 (or 9126 counting only the distinct ones).

The product of its digits is 16128, while the sum is 36.

The square root of 128212749 is about 11323.1068616348. The cubic root of 128212749 is about 504.2474809718.

The spelling of 128212749 in words is "one hundred twenty-eight million, two hundred twelve thousand, seven hundred forty-nine".