661335444 has 144 divisors (see below), whose sum is σ = 2095382016. Its totient is φ = 170856000.

The previous prime is 661335443. The next prime is 661335461. The reversal of 661335444 is 444533166.

661335444 is a `hidden beast` number, since 6 + 613 + 35 + 4 + 4 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 661335399 and 661335408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661335443) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 628719 + ... + 629769.

It is an arithmetic number, because the mean of its divisors is an integer number (14551264).

Almost surely, 2^661335444 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661335444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1047691008).

661335444 is an abundant number, since it is smaller than the sum of its proper divisors (1434046572).

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

661335444 is a wasteful number, since it uses less digits than its factorization.

661335444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306 (or 1301 counting only the distinct ones).

The product of its digits is 103680, while the sum is 36.

The square root of 661335444 is about 25716.4430666451. The cubic root of 661335444 is about 871.2456038125.

The spelling of 661335444 in words is "six hundred sixty-one million, three hundred thirty-five thousand, four hundred forty-four".