1645517265121 has 4 divisors (see below), whose sum is σ = 1645775230000. Its totient is φ = 1645259300244.

The previous prime is 1645517265113. The next prime is 1645517265143. The reversal of 1645517265121 is 1215627155461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1645517265121 - 2³ = 1645517265113 is a prime.

It is a super-2 number, since 2×1645517265121² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1645517265101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 128972871 + ... + 128985628.

It is an arithmetic number, because the mean of its divisors is an integer number (411443807500).

Almost surely, 2^{1645517265121} is an apocalyptic number.

It is an amenable number.

1645517265121 is a deficient number, since it is larger than the sum of its proper divisors (257964879).

1645517265121 is an equidigital number, since it uses as much as digits as its factorization.

1645517265121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 257964878.

The product of its digits is 504000, while the sum is 46.

The spelling of 1645517265121 in words is "one trillion, six hundred forty-five billion, five hundred seventeen million, two hundred sixty-five thousand, one hundred twenty-one".