661320543004541 has 32 divisors (see below), whose sum is σ = 784284110979840. Its totient is φ = 545601342375936.

The previous prime is 661320543004531. The next prime is 661320543004547. The reversal of 661320543004541 is 145400345023166.

It is not a de Polignac number, because 661320543004541 - 2²² = 661320538810237 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661320543004492 and 661320543004501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661320543004547) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 316860095 + ... + 318940371.

It is an arithmetic number, because the mean of its divisors is an integer number (24508878468120).

Almost surely, 2^{661320543004541} is an apocalyptic number.

It is an amenable number.

661320543004541 is a deficient number, since it is larger than the sum of its proper divisors (122963567975299).

661320543004541 is a wasteful number, since it uses less digits than its factorization.

661320543004541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2085173.

The product of its (nonzero) digits is 1036800, while the sum is 44.

The spelling of 661320543004541 in words is "six hundred sixty-one trillion, three hundred twenty billion, five hundred forty-three million, four thousand, five hundred forty-one".