1667221660 has 48 divisors (see below), whose sum is σ = 3780124992. Its totient is φ = 614016000.

The previous prime is 1667221651. The next prime is 1667221667. The reversal of 1667221660 is 661227661.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1667221667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 96265 + ... + 112255.

It is an arithmetic number, because the mean of its divisors is an integer number (78752604).

Almost surely, 2^1667221660 is an apocalyptic number.

1667221660 is a gapful number since it is divisible by the number (10) 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 1667221660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1890062496).

1667221660 is an abundant number, since it is smaller than the sum of its proper divisors (2112903332).

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

1667221660 is a wasteful number, since it uses less digits than its factorization.

1667221660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16414 (or 16412 counting only the distinct ones).

The product of its (nonzero) digits is 36288, while the sum is 37.

The square root of 1667221660 is about 40831.6257330026. The cubic root of 1667221660 is about 1185.7626903630.

The spelling of 1667221660 in words is "one billion, six hundred sixty-seven million, two hundred twenty-one thousand, six hundred sixty".