1280006400128 has 16 divisors (see below), whose sum is σ = 2550012750510. Its totient is φ = 640003200000.

The previous prime is 1280006400121. The next prime is 1280006400151. The reversal of 1280006400128 is 8210046000821.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 646403136064 + 633603264064 = 803992^2 + 795992^2 .

It is a tau number, because it is divible by the number of its divisors (16).

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 = 1280006400094 and 1280006400103.

It is not an unprimeable number, because it can be changed into a prime (1280006400121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5000024873 + ... + 5000025128.

Almost surely, 2^{1280006400128} is an apocalyptic number.

It is an amenable number.

1280006400128 is a deficient number, since it is larger than the sum of its proper divisors (1270006350382).

1280006400128 is an equidigital number, since it uses as much as digits as its factorization.

1280006400128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10000050015 (or 10000050003 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 32.

1280006400128 divided by its sum of digits (32) gives a palindrome (40000200004).

The spelling of 1280006400128 in words is "one trillion, two hundred eighty billion, six million, four hundred thousand, one hundred twenty-eight".