661487143 has 4 divisors (see below), whose sum is σ = 661543848. Its totient is φ = 661430440.

The previous prime is 661487137. The next prime is 661487149. The reversal of 661487143 is 341784166.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (661487137) and next prime (661487149).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661487143 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 661487096 and 661487105.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661487149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3721 + ... + 36562.

It is an arithmetic number, because the mean of its divisors is an integer number (165385962).

Almost surely, 2^661487143 is an apocalyptic number.

661487143 is a deficient number, since it is larger than the sum of its proper divisors (56705).

661487143 is a wasteful number, since it uses less digits than its factorization.

661487143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56704.

The product of its digits is 96768, while the sum is 40.

The square root of 661487143 is about 25719.3923528531. The cubic root of 661487143 is about 871.3122149822.

The spelling of 661487143 in words is "six hundred sixty-one million, four hundred eighty-seven thousand, one hundred forty-three".