661843612 has 12 divisors (see below), whose sum is σ = 1158693480. Its totient is φ = 330788336.

The previous prime is 661843603. The next prime is 661843627. The reversal of 661843612 is 216348166.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21763 + ... + 42394.

It is an arithmetic number, because the mean of its divisors is an integer number (96557790).

Almost surely, 2^661843612 is an apocalyptic number.

It is an amenable number.

661843612 is a deficient number, since it is larger than the sum of its proper divisors (496849868).

661843612 is a wasteful number, since it uses less digits than its factorization.

661843612 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66740 (or 66738 counting only the distinct ones).

The product of its digits is 41472, while the sum is 37.

The square root of 661843612 is about 25726.3213849163. The cubic root of 661843612 is about 871.4687007742.

It can be divided in two parts, 66184 and 3612, that added together give a palindrome (69796).

The spelling of 661843612 in words is "six hundred sixty-one million, eight hundred forty-three thousand, six hundred twelve".