128769749 has 4 divisors (see below), whose sum is σ = 128840160. Its totient is φ = 128699340.

The previous prime is 128769743. The next prime is 128769761. The reversal of 128769749 is 947967821.

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, and also an emirpimes, since its reverse is a distinct semiprime: 947967821 = 17 ⋅55762813.

It is a cyclic number.

It is not a de Polignac number, because 128769749 - 2¹² = 128765653 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 128769749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (128769743) 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, 32387 + ... + 36144.

It is an arithmetic number, because the mean of its divisors is an integer number (32210040).

Almost surely, 2^128769749 is an apocalyptic number.

It is an amenable number.

128769749 is a deficient number, since it is larger than the sum of its proper divisors (70411).

128769749 is an equidigital number, since it uses as much as digits as its factorization.

128769749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70410.

The product of its digits is 1524096, while the sum is 53.

The square root of 128769749 is about 11347.6759294580. The cubic root of 128769749 is about 504.9766338893.

The spelling of 128769749 in words is "one hundred twenty-eight million, seven hundred sixty-nine thousand, seven hundred forty-nine".