661407543 has 6 divisors (see below), whose sum is σ = 955366464. Its totient is φ = 440938356.

The previous prime is 661407541. The next prime is 661407557. The reversal of 661407543 is 345704166.

It is a happy number.

It is not a de Polignac number, because 661407543 - 2¹ = 661407541 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 661407498 and 661407507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661407541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 36744855 + ... + 36744872.

It is an arithmetic number, because the mean of its divisors is an integer number (159227744).

Almost surely, 2^661407543 is an apocalyptic number.

661407543 is a deficient number, since it is larger than the sum of its proper divisors (293958921).

661407543 is a wasteful number, since it uses less digits than its factorization.

661407543 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73489733 (or 73489730 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The square root of 661407543 is about 25717.8448358333. The cubic root of 661407543 is about 871.2772638194.

The spelling of 661407543 in words is "six hundred sixty-one million, four hundred seven thousand, five hundred forty-three".