1239664128 has 80 divisors (see below), whose sum is σ = 3310542576. Its totient is φ = 412221440.

The previous prime is 1239664121. The next prime is 1239664147. The reversal of 1239664128 is 8214669321.

It is a self number, because there is not a number n which added to its sum of digits gives 1239664128.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1239664121) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 910168 + ... + 911528.

Almost surely, 2^1239664128 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 1239664128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1655271288).

1239664128 is an abundant number, since it is smaller than the sum of its proper divisors (2070878448).

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

1239664128 is an equidigital number, since it uses as much as digits as its factorization.

1239664128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1975 (or 1959 counting only the distinct ones).

The product of its digits is 124416, while the sum is 42.

The square root of 1239664128 is about 35208.8643384021. The cubic root of 1239664128 is about 1074.2400622994.

The spelling of 1239664128 in words is "one billion, two hundred thirty-nine million, six hundred sixty-four thousand, one hundred twenty-eight".