661334400 has 144 divisors (see below), whose sum is σ = 2359895460. Its totient is φ = 176348160.

The previous prime is 661334389. The next prime is 661334419. The reversal of 661334400 is 4433166.

661334400 is a `hidden beast` number, since 6 + 613 + 3 + 4 + 40 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 17319 + ... + 40281.

Almost surely, 2^661334400 is an apocalyptic number.

661334400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661334400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1179947730).

661334400 is an abundant number, since it is smaller than the sum of its proper divisors (1698561060).

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

661334400 is a wasteful number, since it uses less digits than its factorization.

661334400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22993 (or 22973 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 661334400 is about 25716.4227683401. The cubic root of 661334400 is about 871.2451453559.

Adding to 661334400 its reverse (4433166), we get a palindrome (665767566).

The spelling of 661334400 in words is "six hundred sixty-one million, three hundred thirty-four thousand, four hundred".