661785468 has 12 divisors (see below), whose sum is σ = 1544166120. Its totient is φ = 220595152.

The previous prime is 661785457. The next prime is 661785493. The reversal of 661785468 is 864587166.

It is a tau number, because it is divible by the number of its divisors (12).

It is a self number, because there is not a number n which added to its sum of digits gives 661785468.

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, 27574383 + ... + 27574406.

It is an arithmetic number, because the mean of its divisors is an integer number (128680510).

Almost surely, 2^661785468 is an apocalyptic number.

It is an amenable number.

661785468 is an abundant number, since it is smaller than the sum of its proper divisors (882380652).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661785468 is a wasteful number, since it uses less digits than its factorization.

661785468 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55148796 (or 55148794 counting only the distinct ones).

The product of its digits is 1935360, while the sum is 51.

The square root of 661785468 is about 25725.1913112420. The cubic root of 661785468 is about 871.4431800625.

The spelling of 661785468 in words is "six hundred sixty-one million, seven hundred eighty-five thousand, four hundred sixty-eight".