3129728 has 48 divisors (see below), whose sum is σ = 7267500. Its totient is φ = 1338624.

The previous prime is 3129701. The next prime is 3129733. The reversal of 3129728 is 8279213.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a junction number, because it is equal to n+sod(n) for n = 3129694 and 3129703.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6023 + ... + 6521.

Almost surely, 2^3129728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 3129728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3633750).

3129728 is an abundant number, since it is smaller than the sum of its proper divisors (4137772).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

3129728 is an equidigital number, since it uses as much as digits as its factorization.

3129728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 527 (or 508 counting only the distinct ones).

The product of its digits is 6048, while the sum is 32.

The square root of 3129728 is about 1769.1037278803. The cubic root of 3129728 is about 146.2745817886.

The spelling of 3129728 in words is "three million, one hundred twenty-nine thousand, seven hundred twenty-eight".