1289920840345 has 16 divisors (see below), whose sum is σ = 1548635078160. Its totient is φ = 1031450112000.

The previous prime is 1289920840319. The next prime is 1289920840349. The reversal of 1289920840345 is 5430480299821.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 3064286736 + 1286856553609 = 55356^2 + 1134397^2 .

It is not a de Polignac number, because 1289920840345 - 2²⁵ = 1289887285913 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1289920840349) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 192838761 + ... + 192845449.

It is an arithmetic number, because the mean of its divisors is an integer number (96789692385).

Almost surely, 2^{1289920840345} is an apocalyptic number.

It is an amenable number.

1289920840345 is a deficient number, since it is larger than the sum of its proper divisors (258714237815).

1289920840345 is an equidigital number, since it uses as much as digits as its factorization.

1289920840345 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19116.

The product of its (nonzero) digits is 4976640, while the sum is 55.

The spelling of 1289920840345 in words is "one trillion, two hundred eighty-nine billion, nine hundred twenty million, eight hundred forty thousand, three hundred forty-five".