661543143 has 4 divisors (see below), whose sum is σ = 882057528. Its totient is φ = 441028760.

The previous prime is 661543123. The next prime is 661543171. The reversal of 661543143 is 341345166.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 661543143 - 2⁶ = 661543079 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661543123) 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, 110257188 + ... + 110257193.

It is an arithmetic number, because the mean of its divisors is an integer number (220514382).

Almost surely, 2^661543143 is an apocalyptic number.

661543143 is a deficient number, since it is larger than the sum of its proper divisors (220514385).

661543143 is a wasteful number, since it uses less digits than its factorization.

661543143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 220514384.

The product of its digits is 25920, while the sum is 33.

The square root of 661543143 is about 25720.4810025007. The cubic root of 661543143 is about 871.3368020599.

It can be divided in two parts, 661543 and 143, that multiplied together give a palindrome (94600649).

The spelling of 661543143 in words is "six hundred sixty-one million, five hundred forty-three thousand, one hundred forty-three".