661368 has 32 divisors (see below), whose sum is σ = 1751760. Its totient is φ = 207360.

The previous prime is 661361. The next prime is 661373. The reversal of 661368 is 863166.

661368 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661361) by changing a digit.

661368 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 403 + ... + 1218.

2⁶⁶¹³⁶⁸ is an apocalyptic number.

661368 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

661368 is an abundant number, since it is smaller than the sum of its proper divisors (1090392).

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

661368 is a wasteful number, since it uses less digits than its factorization.

661368 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1647 (or 1643 counting only the distinct ones).

The product of its digits is 5184, while the sum is 30.

The square root of 661368 is about 813.2453504325. The cubic root of 661368 is about 87.1259900040.

The spelling of 661368 in words is "six hundred sixty-one thousand, three hundred sixty-eight".