661348800 has 462 divisors, whose sum is σ = 2789695208. Its totient is φ = 151165440.

The previous prime is 661348783. The next prime is 661348801. The reversal of 661348800 is 8843166.

It is a happy number.

It is a super-2 number, since 2×661348800² = 874764470522880000, which contains 22 as substring.

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

It is a Saint-Exupery number, since it is equal to the product of the sides of a Pythagorean triangle: 1350 × 378 × 1296.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661348801) by changing a digit.

It is a polite number, since it can be written in 65 ways as a sum of consecutive naturals, for example, 94478397 + ... + 94478403.

Almost surely, 2^661348800 is an apocalyptic number.

661348800 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 661348800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1394847604).

661348800 is an abundant number, since it is smaller than the sum of its proper divisors (2128346408).

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

661348800 is an frugal number, since it uses more digits than its factorization.

661348800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59 (or 17 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 661348800 is about 25716.7027435478. The cubic root of 661348800 is about 871.2514688533.

The spelling of 661348800 in words is "six hundred sixty-one million, three hundred forty-eight thousand, eight hundred".