1669408138945 has 16 divisors (see below), whose sum is σ = 2024186422608. Its totient is φ = 1321598730240.

The previous prime is 1669408138943. The next prime is 1669408138961. The reversal of 1669408138945 is 5498318049661.

It can be written as a sum of positive squares in 8 ways, for example, as 65251637136 + 1604156501809 = 255444^2 + 1266553^2 .

It is not a de Polignac number, because 1669408138945 - 2¹ = 1669408138943 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1669408138943) 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, 3900177 + ... + 4306993.

It is an arithmetic number, because the mean of its divisors is an integer number (126511651413).

Almost surely, 2^{1669408138945} is an apocalyptic number.

It is an amenable number.

1669408138945 is a deficient number, since it is larger than the sum of its proper divisors (354778283663).

1669408138945 is an equidigital number, since it uses as much as digits as its factorization.

1669408138945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 415380.

The product of its (nonzero) digits is 44789760, while the sum is 64.

The spelling of 1669408138945 in words is "one trillion, six hundred sixty-nine billion, four hundred eight million, one hundred thirty-eight thousand, nine hundred forty-five".