1342643521561 has 4 divisors (see below), whose sum is σ = 1347748630272. Its totient is φ = 1337538412852.

The previous prime is 1342643521553. The next prime is 1342643521567. The reversal of 1342643521561 is 1651253462431.

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 1342643521561 - 2³ = 1342643521553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1342643521567) 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, 2552553961 + ... + 2552554486.

It is an arithmetic number, because the mean of its divisors is an integer number (336937157568).

Almost surely, 2^{1342643521561} is an apocalyptic number.

It is an amenable number.

1342643521561 is a deficient number, since it is larger than the sum of its proper divisors (5105108711).

1342643521561 is an equidigital number, since it uses as much as digits as its factorization.

1342643521561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5105108710.

The product of its digits is 518400, while the sum is 43.

Adding to 1342643521561 its reverse (1651253462431), we get a palindrome (2993896983992).

The spelling of 1342643521561 in words is "one trillion, three hundred forty-two billion, six hundred forty-three million, five hundred twenty-one thousand, five hundred sixty-one".