1643420243461 has 4 divisors (see below), whose sum is σ = 1643682065932. Its totient is φ = 1643158420992.

The previous prime is 1643420243419. The next prime is 1643420243557.

1643420243461 is nontrivially palindromic in base 10.

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 1500210978561 + 143209264900 = 1224831^2 + 378430^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1643420243461 is a prime.

It is a super-3 number, since 3×1643420243461³ (a number of 38 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643420247461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 130901820 + ... + 130914373.

It is an arithmetic number, because the mean of its divisors is an integer number (410920516483).

Almost surely, 2^{1643420243461} is an apocalyptic number.

It is an amenable number.

1643420243461 is a deficient number, since it is larger than the sum of its proper divisors (261822471).

1643420243461 is an equidigital number, since it uses as much as digits as its factorization.

1643420243461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261822470.

The product of its (nonzero) digits is 331776, while the sum is 40.

It can be divided in two parts, 1643420 and 243461, that added together give a palindrome (1886881).

The spelling of 1643420243461 in words is "one trillion, six hundred forty-three billion, four hundred twenty million, two hundred forty-three thousand, four hundred sixty-one".