661364543 has 4 divisors (see below), whose sum is σ = 755845200. Its totient is φ = 566883888.

The previous prime is 661364449. The next prime is 661364567. The reversal of 661364543 is 345463166.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 345463166 = 2 ⋅172731583.

It is a cyclic number.

It is not a de Polignac number, because 661364543 - 2¹⁰ = 661363519 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661364497 and 661364506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661364573) 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, 47240318 + ... + 47240331.

It is an arithmetic number, because the mean of its divisors is an integer number (188961300).

Almost surely, 2^661364543 is an apocalyptic number.

661364543 is a deficient number, since it is larger than the sum of its proper divisors (94480657).

661364543 is an equidigital number, since it uses as much as digits as its factorization.

661364543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94480656.

The product of its digits is 155520, while the sum is 38.

The square root of 661364543 is about 25717.0088268445. The cubic root of 661364543 is about 871.2583819996.

The spelling of 661364543 in words is "six hundred sixty-one million, three hundred sixty-four thousand, five hundred forty-three".