321661600 has 144 divisors (see below), whose sum is σ = 855367128. Its totient is φ = 117411840.

The previous prime is 321661597. The next prime is 321661631. The reversal of 321661600 is 6166123.

It can be written as a sum of positive squares in 12 ways, for example, as 22924944 + 298736656 = 4788^2 + 17284^2 .

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1632702 + ... + 1632898.

Almost surely, 2^321661600 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 321661600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (427683564).

321661600 is an abundant number, since it is smaller than the sum of its proper divisors (533705528).

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

321661600 is a wasteful number, since it uses less digits than its factorization.

321661600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 387 (or 374 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 321661600 is about 17934.9268189196. The cubic root of 321661600 is about 685.1722088210.

The spelling of 321661600 in words is "three hundred twenty-one million, six hundred sixty-one thousand, six hundred".