42561435453521 has 4 divisors (see below), whose sum is σ = 43144468815972. Its totient is φ = 41978402091072.

The previous prime is 42561435453517. The next prime is 42561435453539. The reversal of 42561435453521 is 12535453416524.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 30997457111296 + 11563978342225 = 5567536^2 + 3400585^2 .

It is a cyclic number.

It is not a de Polignac number, because 42561435453521 - 2² = 42561435453517 is a prime.

It is a super-2 number, since 2×42561435453521² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 42561435453521.

It is not an unprimeable number, because it can be changed into a prime (42561435453571) 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, 291516681116 + ... + 291516681261.

It is an arithmetic number, because the mean of its divisors is an integer number (10786117203993).

Almost surely, 2^{42561435453521} is an apocalyptic number.

It is an amenable number.

42561435453521 is a deficient number, since it is larger than the sum of its proper divisors (583033362451).

42561435453521 is an equidigital number, since it uses as much as digits as its factorization.

42561435453521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 583033362450.

The product of its digits is 8640000, while the sum is 50.

The spelling of 42561435453521 in words is "forty-two trillion, five hundred sixty-one billion, four hundred thirty-five million, four hundred fifty-three thousand, five hundred twenty-one".