321665740 has 48 divisors (see below), whose sum is σ = 747038880. Its totient is φ = 115361280.

The previous prime is 321665731. The next prime is 321665761. The reversal of 321665740 is 47566123.

It is a happy number.

It is a Smith number, since the sum of its digits (34) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 321665696 and 321665705.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6046 + ... + 26074.

It is an arithmetic number, because the mean of its divisors is an integer number (15563310).

Almost surely, 2^321665740 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 321665740, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (373519440).

321665740 is an abundant number, since it is smaller than the sum of its proper divisors (425373140).

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

321665740 is a wasteful number, since it uses less digits than its factorization.

321665740 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20122 (or 20120 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 321665740 is about 17935.0422358020. The cubic root of 321665740 is about 685.1751483499.

The spelling of 321665740 in words is "three hundred twenty-one million, six hundred sixty-five thousand, seven hundred forty".