661543142 has 16 divisors (see below), whose sum is σ = 1091385792. Its totient is φ = 298830720.

The previous prime is 661543123. The next prime is 661543171. The reversal of 661543142 is 241345166.

It is a junction number, because it is equal to n+sod(n) for n = 661543099 and 661543108.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 269459 + ... + 271902.

It is an arithmetic number, because the mean of its divisors is an integer number (68211612).

Almost surely, 2^661543142 is an apocalyptic number.

661543142 is a deficient number, since it is larger than the sum of its proper divisors (429842650).

661543142 is a wasteful number, since it uses less digits than its factorization.

661543142 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 541423.

The product of its digits is 17280, while the sum is 32.

The square root of 661543142 is about 25720.4809830610. The cubic root of 661543142 is about 871.3368016208.

It can be divided in two parts, 66154 and 3142, that added together give a palindrome (69296).

The spelling of 661543142 in words is "six hundred sixty-one million, five hundred forty-three thousand, one hundred forty-two".